Digital single-lens reflex camera including control section that performs camera shake correction and motion detecting section that detects speed of subject

ABSTRACT

A digital single-lens reflex camera is configured for making it possible to reduce deterioration in image quality due to a camera shake or an object movement and to easily pick up an image with a good image quality. In a digital single-lens reflex camera ( 1 ), when an object speed is detected on the basis of a detected object movement, a body microprocessor ( 12 ) judges if the object speed is equal to a threshold value (A) or more and, if it is smaller than the threshold value (A), controls a conversion lens camera shake correcting device ( 82 ) in a conversion lens ( 2 ) or a camera body shake correcting device ( 75 ) in a camera body ( 3 ) to carry out the camera shake correction. Further, if the object speed is equal to or more than the threshold value (A), the body microprocessor ( 12 ) makes a digital signal gain setting unit ( 111 ) high in gain so as to increase the ISO sensitivity or makes a shatter speed faster to set a shorter exposure time and has a plurality of images continuously picked up under different exposure conditions.

TECHNICAL FIELD

The present invention relates to a digital single-lens reflex camera.More particularly, the present invention relates to a lens-replaceabledigital single-lens reflex camera with a camera shake correctingfunction and a photographing sensitivity changing function.

BACKGROUND ART

Imaging apparatuses such as digital still cameras and digital videocameras capable of converting an optical image of the subject to anelectrical image signal and outputting the image signal (hereinaftersimply referred to as “digital cameras”) are rapidly becomingwidespread. With reductions in size and weight and escalation in themagnification of optical zooming in recent years in particular, digitalcameras have become significantly convenient for photographers (users).

Furthermore, lens-replaceable digital single-lens reflex cameras arerapidly becoming widespread in recent years. When the photographer seesthe subject through a finder, this digital single-lens reflex cameracauses light incident upon the photographing lens (that is, the image ofthe subject) to be reflected by a reflecting mirror placed on thephotographing optical path after the lens, to change the optical path,converts the image of the subject image to an erect image through apentaprism and so on, and guides the image of the subject to an opticalfinder. This allows the photographer to see the subject image throughthe lens from the optical finder. Therefore, the position where thefinder optical path is formed normally is the regular position of thereflecting mirror.

On the other hand, if the lens is used to take photographs, thereflecting mirror immediately changes its position and is retracted fromthe photographing optical path, thereby switching the finder opticalpath to the photographing optical path. When photographs have beentaken, the reflecting mirror immediately returns to the regularposition. This scheme is common to a conventional film camera and adigital camera which adopt a single-lens reflex scheme.

One feature of a digital camera is that it is possible to photograph asubject by looking at the display apparatus (e.g. liquid crystalmonitor) when a photograph is taken and check the photographed imageimmediately after taking a photograph. However, using the existingreflecting mirror scheme of digital single-lens reflex cameras entails aproblem that the liquid crystal monitor cannot be used when a photographis taken. Therefore, with an existing digital single-lens reflex camera,it is not possible to take a photograph using the liquid crystal monitorby looking into the finder and this is very inconvenient to a beginnerwho is unfamiliar with taking photographs using a digital camera inparticular. Therefore, as shown in Patent Document 1, there is a demandfor a function to allow the user to take a photograph using a liquidcrystal monitor also when taking a photograph.

However, accompanying reductions in size and weight of not only digitalsingle-lens reflex cameras but also digital cameras and escalation inthe magnification of optical zooming, especially when a beginner uses adigital camera, a “blur” may occur in photographed images and may causeimage quality degradation.

Patent Document 2 discloses a digital camera with a blur correctingoptical system capable of reducing the influence on an image even whencamera shake (which will be described later) occurs when a photograph istaken. The digital camera described in Patent Document 2 moves thecorrection lens up, down, left and right in directions perpendicular tothe optical axis, depending on image shake of when a photograph istaken, and corrects image distortion. By this means, it is possible totake a photograph with reduced image shake using a smaller-sized andlighter-weighted digital camera. Furthermore, the digital cameradisclosed in Patent Document 2 does not have to use a flash to emitlight upon taking a photograph to prevent image shake, so that it ispossible to take a photograph under conditions producing similaratmosphere to natural colors.

On the other hand, possible causes of image quality degradation ofphotographed images include “subject shake” caused by the motion of thesubject, in addition to “camera shake” caused by vibration added to thecamera by a shaking hand. Subject shake can be prevented by makingexposure time shorter and taking a photograph at a high shutter speed.Shutter speed can be made faster by, for example, increasingphotographing sensitivity or by using a flash light. As for opticalimage shake of the subject in the imaging plane, shake caused byvibration applied to the camera, will be referred to as “camera shake”and shake caused by the motion of the subject will be referred to as“subject shake” and camera shake and subject shake will be collectivelyreferred to as “image shake with respect to the imaging plane.”

Patent Document 3 discloses a photographing apparatus with a motionprediction means for predicting the motion of the subject and changingphotographing conditions such as shutter speed when the subject islikely to move, and a method applicable with the apparatus.

-   Patent Document 1: Japanese Patent Application Laid-Open No.    2001-125173-   Patent Document 2: Japanese Patent Application Laid-Open No.    2000-13671-   Patent Document 3: Japanese Patent Application Laid-Open No.    2006-157428

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

Generally, when photographing sensitivity is increased, the outputsignal from the imaging sensor is amplified, and, consequently, noiseproduced from the imaging sensor is also amplified. Therefore, an imagetaken in high sensitivity contains a large amount of noise. Increasingphotographing sensitivity more than necessary may thus result in imagequality degradation. It is therefore preferable to increasephotographing sensitivity exclusively when camera shake still occurs dueto insufficient ambient brightness after correction by the correctingoptical system or when a fast-moving subject is photographed.

However, with such a conventional digital camera, it is difficult forphotographers to know what level of moving speed of the subject causessubject shake. Therefore, cases often occur where even though it ispossible to take a photograph without subject shake the photographerobserving the motion of the subject misjudges that subject shake willoccur. As a result, there is a problem that the photographers changephotographing sensitivity to high sensitivity and take a photographcontaining a large amount of noise more than necessary. Furthermore,there is a problem that when taking a photograph of a fast-movingsubject, photographers need to change photographing sensitivityimmediately before taking a photograph and might miss the chance to takea photograph if photographing sensitivity changes slowly.

That is, a general photographer cannot identify what level of movingspeed of the subject will or will not cause subject shake. In otherwords, using the camera shake correcting function may result in taking aphotograph with subject shake when the subject is moving fast, or,conversely, increasing photographing sensitivity may result in taking aphotograph with a large amount of noise when the subject is movingslowly, and taking photographs in good quality is not possible in eithercase.

Furthermore, although the digital camera having a blur correctingoptical system disclosed in Patent Document 2 can reduce image qualitydegradation due to camera shake, there is no proposal of alleviatingimage quality degradation caused by subject shake.

Furthermore, since the digital camera disclosed in Patent Document 3 isonly directed to predicting the motion of the subject and is notdirected to finding out what level of moving speed of the subject willor will not cause subject shake, it is not always possible to take aphotograph at an optimal shutter speed suitable for the speed of thesubject.

It is therefore an object of the present invention to provide a digitalsingle-lens reflex camera that reduces image quality degradation due tocamera shake or subject shake and that enables images of good quality tobe photographed in a simple way.

Means for Solving the Problem

The digital single-lens reflex camera of the present invention is adigital single lens reflex camera with an imaging sensor and a returnmirror, the camera adopting a configuration having: a focusing sectionthat performs focus detection based on a contrast scheme using theimaging sensor; a motion detecting section that detects a speed of thesubject based on an image on the imaging sensor; and a control sectionthat performs camera shake correction according to the speed of thesubject detected in the motion detecting section, and, with this camera,the focusing section, the motion detecting section and the controlsection enter operation mode while the return mirror is retracted fromthe optical axis.

Advantageous Effect of the Invention

According to the present invention, it is possible, also with a digitalsingle-lens reflex camera, to reduce image quality degradation due tocamera shake or subject shake, and take images of high image qualityeasily.

For example, if the subject speed is equal to or above a predeterminedvalue (threshold), it is possible to perform continuous shooting by aplurality of exposure conditions by increasing ISO sensitivity orsetting a faster shutter speed. Even if the moving speed of the subjectchanges substantially while taking photographs, continuous shooting by aplurality of exposure conditions increases the likelihood that images ofhigh image quality may be included among the plurality of photographedon a continuous basis images under the plurality of exposure conditions.On the other hand, if the subject speed is below the predetermined value(threshold), operating the camera shake correcting function makes itpossible to photograph images of high quality free of image shake. As aresult, the photographer can photograph image in high image qualityeasily regardless of the motion of the subject.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing an overall configuration of a digitalsingle-lens reflex camera according to an embodiment of the presentinvention;

FIG. 2 is a block diagram mainly showing an example of a configurationof a control system in the configuration of the camera body shown inFIG. 1;

FIG. 3 is a block diagram mainly showing an example of a configurationof an operation system in the configuration of the camera body shown inFIG. 1;

FIG. 4 is a schematic view showing an example of an outer configurationof the camera body shown in FIG. 1: FIG. 4A showing a top view; and FIG.4B showing a plan view;

FIG. 5 is a block diagram showing an example of a configuration of themotion detecting section shown in FIG. 2;

FIG. 6 is a block diagram mainly showing an example in the configurationof the control system in the configuration of the replacement lens shownin FIG. 1;

FIG. 7 is a block diagram showing an example of the control system ofthe camera shake correcting apparatus included in the replacement lensshown in FIG. 1;

FIG. 8 is a conceptual diagram illustrating finder photographing mode inthe present embodiment;

FIG. 9 is a conceptual diagram illustrating monitor photographing modein the present embodiment;

FIG. 10 is a block diagram showing a modification example of the digitalsingle-lens reflex camera shown in FIG. 1;

FIG. 11 is a flowchart showing a sequence regarding a selectionoperation by the camera shake correcting apparatus in the presentembodiment;

FIG. 12 shows a display example of a photographing mode selecting screendisplayed on the display section in the present embodiment;

FIG. 13 is a flowchart showing the procedures of photographing processby the digital single-lens reflex camera according to the presentembodiment;

FIG. 14 shows a display example of an image photographed in camera shakecorrection mode and displayed on the display section of the digitalsingle-lens reflex camera according to the present embodiment;

FIG. 15 illustrates a relationship between a combination of camera shakecorrecting apparatuses in the replacement lens and the camera body ofthe digital single-lens reflex camera according to the presentembodiment and a threshold;

FIG. 16 illustrates a moving speed Vh of the subject based on athreshold A and switching of photographing sensitivity S when aphotograph is taken according to the present embodiment;

FIG. 17 illustrates a relationship between the moving speed Vh of thesubject and photographing sensitivity S when a photograph is takenaccording to the present embodiment; and

FIG. 18 shows a display example of a photographed image with asensitivity increase and a photographed image without a sensitivityincrease displayed together on the display section after photographingsensitivity increasing mode is set in the digital single-lens reflexcamera according to the present embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be explained indetail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an overall configuration of a digitalsingle-lens reflex camera according to an embodiment of the presentinvention, FIG. 2 is a block diagram mainly showing an example of aconfiguration of a control system in the configuration of the camerabody shown in FIG. 1 and FIG. 3 is a block diagram mainly showing anexample of a configuration of an operation system in the configurationof the camera body shown in FIG. 1. Furthermore, FIG. 4 is a schematicview showing an example of an outer configuration of the camera bodyshown in FIG. 1 and particularly FIG. 4A shows a top view and FIG. 4Bshows a rear view.

The present embodiment shows a case where the present invention isapplied to a digital single-lens reflex camera with a camera shakecorrecting function and a photographing sensitivity changing function.In the following explanations, the moving speed of the subject(hereinafter also referred to as “subject speed”) means the moving speedof an optical image of the subject on the imaging plane caused by one ofcamera shake and subject shake or both.

(Overall Configuration of Digital Single-Lens Reflex Camera 1)

In FIG. 1, digital single-lens reflex camera 1 is a replacement lenstype digital single-lens reflex camera and is primarily comprised ofcamera body 3 that has main functions of digital single-lens reflexcamera 1 and replacement lens 2 detachably mounted in camera body 3.Replacement lens 2 is mounted in body mount 81 provided in the front ofcamera body 3 via lens mount 80 provided in the rearmost part.

[Configuration of Camera Body 3]

In FIG. 1 to FIG. 3, camera body 3 is mainly comprised of imagingsection 71 that picks up an image of the subject (including, forexample, imaging sensor 11 and imaging sensor control section 13), bodymicrocomputer 12 that controls the operations of the individual sectionsof imaging section 71 and so on as a body control section, image displaysection 72 that displays a photographed image and various types ofinformation (including, for example, image display control section 15and display section 16), image storage section 73 that stores image data(including, for example, image recording control section 17 and imagereading/recording section 18) and finder optical system 19 that visuallyrecognizes the image of the subject. As shown in further detail in FIG.2 in particular, camera body 3 includes motion detecting section 100that processes an electric signal from imaging section 71 (for details,see FIG. 5 (which will be described later)), digital signalamplification section 110 and digital signal gain setting section 111.

Imaging section 71 is mainly comprised of quick return mirror 4 thatguides incident light to finder optical system 19 and focus detectingunit 5, imaging sensor 11 such as CCD (Charge Coupled Device) thatperforms photoelectric conversion, shutter unit 10 that adjusts theexposure condition of imaging sensor 11, shutter control section 14 thatcontrols the drive of shutter unit 10 based on a control signal frombody microcomputer 12, imaging sensor control section 13 that controlsthe operation of imaging sensor 11, camera body camera shake correctingapparatus 75 that corrects camera shake caused by the shake of digitalsingle-lens reflex camera 1 (see FIG. 2 in particular) and focusdetecting unit 5 that detects the focus (the focus condition of asubject image). Focus detecting unit 5 performs focus detection, forexample, based on a general phase difference detection scheme. As forfocus detection, one of focus detecting unit 5 and a contrast detectionscheme based on image output of imaging sensor 11 (which will bedescribed later) is used depending on the operating situation of digitalsingle-lens reflex camera 1. For example, as will be described later,focus detecting unit 5 is used as a focus detecting means in finderphotographing mode as with the conventional case, whereas, in monitorphotographing mode, quick return mirror 4 is retracted, and thereforecontrast detection is performed using imaging sensor 11 instead of usingfocus detecting unit 5.

Imaging sensor 11 has a function of converting an optical image formedby an imaging optical system L in replacement lens 2 to an electricalsignal, and is, for example, a CCD sensor. Imaging sensor 11 is drivenand controlled by imaging sensor control section 13. Imaging sensor 11may also be a CMOS (Complementary Metal Oxide Semiconductor) sensor.

Body microcomputer 12 is the central system in camera body 3 andcontrols various sequences. To be more specific, body microcomputer 12is mounted with, for example, a CPU, ROM and RAM (not shown), and canimplement various functions by the CPU reading a program stored in theROM. For example, body microcomputer 12 has a function of detecting thatreplacement lens 2 is mounted in camera body 3, a function of selectingwhich of camera shake correcting apparatuses 82 and 75 of replacementlens 2 and camera body 3 is used to perform camera shake correction anda function of setting camera shake correcting apparatus 82 or 75 in anoperation enabled condition or operation disabled condition and so on.As shown in FIG. 1 to FIG. 3, body microcomputer 12 is connected to theindividual sections provided in camera body 3.

Furthermore, body microcomputer 12 executes a photographing controlprocessing for controlling the camera shake correcting function and thephotographing sensitivity changing function depending on the motion ofthe subject. If the subject speed is below a threshold, bodymicrocomputer 12 controls the camera shake correcting apparatus (camerashake correcting apparatus 82 for a replacement lens in replacement lens2 or camera shake correcting apparatus 75 for a camera in camera body 3)to execute camera shake correction or if the subject speed is equal toor above the threshold, body microcomputer 12 increases the gain of thephotographing sensitivity changing function or shortens the exposuretime compared to the case the subject speed is below the threshold andcauses a plurality of images to be photographed on a continuous basisbased on different exposure conditions. Here, as for increasing the gainof the photographing sensitivity changing function and shortening theexposure time, either one or both may be done. Details of photographingcontrol processing will be described later using a flowchart in FIG. 13.Furthermore, body microcomputer 12 can receive signals from power switch52, shutter operation section 53, photographing/playback switchingoperation section 54, operation cross key 55, MENU setting operationsection 56 and SET operation section 57 shown in FIG. 3. Bodymicrocomputer 12 is an example of the control means of the presentinvention.

Furthermore, as shown in FIG. 3, memory section 12 a in bodymicrocomputer 12 stores various types of information about camera body 3(body information). Examples of “body information” include (1)information about the model of camera body 3 for identifying camera body3 (camera-specific information,) such as the name of the manufacturer ofthe camera body, the date of manufacturing, the model, the version ofsoftware installed in body microcomputer 12, and information aboutfirmware update, (2) information as to whether or not camera body 3 ismounted with camera shake correcting apparatus 75, (3) when camera body3 is mounted with camera shake correcting apparatus 75, informationabout detection performance such as the model and sensitivity of shakedetecting section 30 for the body (which will be described later)(body-side detection performance information), (4) information aboutcorrection performance such as model and maximum correctable angle ofcamera shake correcting section 76 for the body (which will be describedlater) (body-side correction performance information), and (5) versionof software for performing camera shake correction and so on.Furthermore, the body information also includes information about powerconsumption necessary to drive camera shake correcting section 76 forthe body (body-side power consumption information) and information abouta drive scheme of camera shake correcting section 76 for the body(body-side drive scheme information). Memory section 12 a can storeinformation transmitted from lens microcomputer 20.

In FIG. 4, casing 3 a of camera body 3 is held by the photographer whenthe subject is photographed. Display section 16, power switch 52,photographing/playback switching operation section 54, operation crosskey 55, MENU setting operation section 56, SET operation section 57 andphotographing mode switching button 58 are provided on the back ofcasing 3 a.

Power switch 52 is an operation unit for turning on and off power todigital single-lens reflex camera 1 or camera body 3. When power switch52 causes power to turn on, power is supplied to the individual sectionsof camera body 3 and replacement lens 2. Photographing/playbackswitching operation section 54 is an operation unit for switchingbetween photographing mode and playback mode and allows the photographerto switch between modes by turning a lever. MENU setting operationsection 56 is an operation unit for setting various operations ofdigital single-lens reflex camera 1. Operation cross key 55 is anoperation unit whereby the photographer presses the upper, lower, leftand right parts to select a desired menu from various menu screensdisplayed on display section 16. SET operation section 57 is anoperation unit for confirming execution of various menus. Photographingmode switching button 58 is an operation unit to switch between twophotographing modes (finder photographing mode and monitor photographingmode) (which will be described later).

In FIG. 4, shutter operation section 53 is provided on the top surfaceof casing 3 a. Shutter operation section 53 is operated by thephotographer when a photograph is taken and is, for example, a releasebutton. When shutter operation section 53 is operated, a timing signalis outputted to body microcomputer 12. Shutter operation section 53 is atwo-stage pushdown switch that allows half-press operation andfull-press operation. When the photographer performs the half-pressoperation, shutter operation section 53 starts motion detection,photometric processing and distance measuring processing for the subject(which will be described later). Furthermore, the half-press operationcauses power to be supplied to individual sections including bodymicrocomputer 12 and lens microcomputer 20. When the photographerperforms the full-press operation, a timing signal is outputted. Shuttercontrol section 14 drives a shutter drive motor (not shown) according toa control signal outputted from body microcomputer 12 which has receivedthe timing signal, and operates shutter unit 10.

Returning to FIG. 2 again, the explanation in the configuration ofcamera body 3 will be continued. In FIG. 2, flash control section 43controls the operation of flash 44. Body microcomputer 12, havingreceived the timing signal outputted through the operation of shutteroperation section 53, outputs a control signal to flash control section43. According to this control signal, flash control section 43 makesflash 44 emit light. Flash 44 is controlled according to the amount oflight received by imaging sensor 11. That is, if the output of the imagesignal from imaging sensor 11 is equal to or less than a predeterminedvalue, flash control section 43 makes flash 44 work with the shutteroperation and emit light automatically. By contrast, if the output ofthe image signal from imaging sensor 11 is equal to or above thepredetermined value, flash control section 43 controls flash 44 not toemit light.

Flash ON/OFF operation section 59 is provided to set the operation offlash 44 irrespective of the output of imaging sensor 11 above. That is,flash control section 43 makes flash 44 emit light when flash ON/OFFoperation section 59 is turned on, and does not make flash 44 emit lightwhen flash ON/OFF operation section 59 is turned off.

The image signal outputted from imaging sensor 11 is sent from analogsignal processing section 66 to A/D conversion section 67, digitalsignal processing section 68, face detecting section 120, digital signalamplification section 110, buffer memory 69, and image compressionsection 70 in sequence and processed. Analog signal processing section66 applies analog signal processing such as gamma processing, to theimage signal outputted from imaging sensor 11. A/D conversion section 67converts the analog signal outputted from analog signal processingsection 66 to a digital signal. Digital signal processing section 68applies digital signal processing such as noise cancellation and contouremphasis to the image signal converted to the digital signal by A/Dconversion section 67 and outputs the signal to motion detecting section100 and digital signal amplification section 110 via face detectingsection 120. Buffer memory 69 is a RAM and stores the image signal on atemporary basis.

Digital signal gain setting section 111 sets the amplification gain forthe image signal after digital signal processing. Digital signalamplification section 110 amplifies the image signal using the setamplification gain and outputs the signal to buffer memory 69. Thesetting of amplification gain is equivalent to setting photographingsensitivity. With the present embodiment, photographing sensitivity isexpressed in values equivalent to ISO sensitivity and can be setequivalent to photographing sensitivity of ISO80, 100, 200, 400, 800,1600 and 3200, for example. Here, photographing sensitivity that can beset is not limited to these. Furthermore, photographing sensitivity maybe expressed in values other than ISO sensitivity equivalents.

Furthermore, the process of amplifying an image signal is notnecessarily performed in digital signal amplification section 110, andmay be performed for an analog signal in analog signal processingsection 66. Furthermore, the amplification process may be performed inimaging sensor 11.

The image signal stored in buffer memory 69 is sent from imagecompression section 70 to image reading/recording section 18 in sequenceand processed. The image signal stored in buffer memory 69 is read outaccording to a command from image recording control section 17 andtransmitted to image compression section 70. Data of the image signaltransmitted to image compression section 70 is compressed according to acommand from image recording control section 17. Through thiscompression process, the image signal is reduced to a smaller data sizethan source data. For example, the JPEG (Joint Photographic ExpertsGroup) scheme is used as the compression method. After that, thecompressed image signal is recorded in image reading/recording section18 by image recording control section 17.

Image reading/recording section 18 is, for example, a built-in memoryand/or a detachable, removable memory that has the function of recordingthe image signal in association with predetermined information to berecorded, based on the command of image recording control section 17.The predetermined information to be recorded together with the imagesignal includes the date and time the image is taken, focal lengthinformation, shutter speed information, F-number information andphotographing mode information. The predetermined information is given,for example, in the Exif (registered trademark) format or formatssimilar to the Exif format.

Display section 16 is, for example, a liquid crystal monitor anddisplays an image signal recorded in image reading/recording section 18or buffer memory 69 in visible image, based on a command from imagedisplay control section 15. Here, the display mode of display section 16includes a display mode in which only image signals are displayed invisible image, and a display mode in which image signals and informationat the time of taking a photograph are displayed in visible images.Display section 16 may also be an angle-variable monitor, the angle ofwhich can be changed freely with respect to casing 3 a of camera body 3.

Motion detecting section 100 detects, on a per frame basis, a vector(hereinafter “motion vector”) showing the amount of position shift inthe horizontal and vertical directions of the image between frames,based on the image signal converted to a digital signal. Hereinafter,the details of motion detecting section 100 will be explained.

FIG. 5 is a block diagram showing an example in the configuration ofabove-described motion detecting section 100. In FIG. 5, motiondetecting section 100 employs a configuration including representativepoint memory 101, correlation calculation section 102 and motion vectordetecting section 103.

Representative point memory 101 divides the image signal of the currentframe inputted via A/D conversion section 67, digital signal processingsection 68 and face detecting section 120 into a plurality of segments,and stores image signals corresponding to the specific representativepoints included in each segment as representative point signals.Furthermore, representative point memory 101 reads out therepresentative point signals from the previously frame of the currentframe that is already stored, and outputs the signals to correlationcalculation section 102.

Correlation calculation section 102 calculates the correlations betweenthe representative signal points from the previous frame and therepresentative signal points in the current frame, and determines thedifferences between the representative signal points. The correlationcalculation result is outputted to motion vector detecting section 103.

Motion vector detecting section 103 detects the motion vector of theimage between the previous frame and the current frame on a per pixelbasis, from the correlation calculation result by correlationcalculation section 102. The detected motion vector is outputted to bodymicrocomputer 12. Body microcomputer 12 adjusts the gain and phase ofthe motion vector and calculates the moving speed and direction of thesubject in the image signal per unit time.

The process of detecting the motion of the subject is started by, forexample, the half-press operation of shutter operation section 53 by thephotographer. The start of the process may also be synchronized with theoperation of turning on power switch 52 and switching to photographingmode by operating photographing/playback switching operation section 54by the photographer.

Returning to FIG. 1, quick return mirror 4 is comprised of main mirror 4a that can reflect and allow to transmit incident light and sub-mirror 4b provided on the back of main mirror 4 a to reflect transmitted lightfrom main mirror 4 a. Quick return mirror 4 can be flipped up outsidethe optical axis AZ by quick return mirror drive control section 60shown in FIG. 3. The incident light is divided into two beams, reflectedbeam and transmitted beam, by main mirror 4 a. Of the two beams, thereflected beam is guided to finder optical system 19. On the other hand,the transmitted beam is reflected by sub-mirror 4 b and used as an AFbeam of focus detecting unit 5. Upon normal photographing, quick returnmirror 4 is flipped up outside the optical axis AZ by quick returnmirror drive control section 60, shutter unit 10 is opened and an imageof the subject is formed on the imaging plane of imaging sensor 11.Furthermore, while a photograph is not taken, quick return mirror 4 isplaced on the optical axis AZ as shown in FIG. 3 and shutter unit 10 isset in a closed position.

Finder optical system 19 is comprised of finder screen 6, on which animage of the subject image is formed, pentaprism 7 that converts thesubject image to an erect image, eyepiece 8 that guides the erect imageof the subject to finder eyepiece window 9 and finder eyepiece window 9for the photographer to see the subject image.

[Configuration of Replacement Lens 2]

FIG. 6 is a block diagram mainly illustrating an example of aconfiguration of a control system in the configuration of thereplacement lens shown in FIG. 1 and FIG. 7 is a block diagramillustrating an example of the control system of the camera shakecorrecting apparatus included in the replacement lens shown in FIG. 1.

In FIG. 1, FIG. 6 and FIG. 7, replacement lens 2 constitutes an imagingoptical system L to form an image of the subject on imaging sensor 11 indigital single-lens reflex camera 1. Replacement lens 2 is comprised offocus lens group 24 that adjusts focus, focus lens group drive controlsection 25 that controls the operation of focus lens group 24, aperturesection 26 that adjusts closing or opening of the aperture, aperturedrive control section 27 that controls the operation of aperture section26, replacement lens camera shake correcting apparatus 82 (see FIG. 7 inparticular) that corrects camera shake by adjusting an optical path andlens microcomputer 20 that controls the operation of replacement lens 2as a lens control section. The configuration of replacement lens camerashake correcting apparatus 82 will be described in further detail later.

Lens microcomputer 20 is a control apparatus that controls the center ofreplacement lens 2 and is connected to individual sections mounted inreplacement lens 2. To be more specific, lens microcomputer 20 ismounted with, for example, a CPU, ROM, and RAM (not shown), and lensmicrocomputer 20 can implement various functions by the CPU reading aprogram stored in the ROM. For example, lens microcomputer 20 has afunction of setting replacement lens camera shake correcting apparatus82 in an operation enabled condition or operation disabled conditionbased on a signal from body microcomputer 12. Furthermore, lensmicrocomputer 20 and body microcomputer 12 are electrically connected tolens mount 80 and body mount 81 via electric pieces (not shown) providedthereon respectively and can transmit/receive information to/from eachother.

Furthermore, memory section 20 a in lens microcomputer 20 stores varioustypes of information about replacement lens 2 (lens information).Examples of “lens information” include (1) information about the modelfor identifying replacement lens 2 (lens-specific information) such asthe name of the manufacturer of replacement lens 2, the date ofmanufacturing, the model, the version of software installed in lensmicrocomputer 20, and information about firmware update, (2) informationas to whether or not replacement lens 2 is mounted with camera shakecorrecting apparatus 82, (3) if replacement lens 2 is mounted withcamera shake correcting apparatus 82, information about detectionperformance such as the model and sensitivity of shake detecting section21 for the lens (which will be described later) (lens-side detectionperformance information), (4) information about correction performancesuch as model and maximum correctable angle of camera shake correctingsection 76 for the replacement lens (which will be described later)(lens-side correction performance information), and (5) the version ofsoftware for performing camera shake correction and so on. Furthermore,the lens information also includes information about power consumptionnecessary to drive replacement lens camera shake correcting section 83(lens-side power consumption information) and information about a drivescheme of replacement lens camera shake correcting section 83 (lens-sidedrive scheme information). Memory section 20 a can store informationtransmitted from body microcomputer 12.

[Configuration of Camera Shake Correcting Apparatus]

Camera body 3 is mounted with camera body camera shake correctingapparatus 75 (see FIG. 2) and replacement lens 2 is mounted withreplacement lens camera shake correcting apparatus 82 (see FIG. 7).

FIG. 2 illustrates an example of a hardware configuration of camera bodycamera shake correcting apparatus 75 and FIG. 7 illustrates an exampleof a hardware configuration of replacement lens camera shake correctingapparatus 82.

First, camera body camera shake correcting apparatus 75 will beexplained.

As shown in FIG. 2, camera body camera shake correcting apparatus 75 isan imaging sensor shift type camera shake correcting apparatus and iscomprised of body shake detecting section 30 that detects the shake ofdigital single-lens reflex camera 1 and body camera shake correctingsection 76 that corrects camera shake according to the amount of shakeof digital single-lens reflex camera 1 detected by body shake detectingsection 30.

Body shake detecting section 30 is comprised of angular velocity sensor85 that detects the motion of digital single-lens reflex camera 1 itselfincluding the imaging optical system L, high pass filter (HPF) 86 thatremoves the DC drift component in unnecessary band components includedin the output of angular velocity sensor 85, low pass filter (LPF) 87that removes the sensor resonance frequency component and noisecomponent in unnecessary band components included in the output ofangular velocity sensor 85, amplifier 88 that adjusts the output signallevel of angular velocity sensor 85 and A/D conversion section 89 thatconverts the output signal of amplifier 88 to a digital signal.

Angular velocity sensor 85 outputs both positive and negative angularvelocity signals depending on the moving direction of digitalsingle-lens reflex camera 1 with reference to the output in a stationarycondition of digital single-lens reflex camera 1. Angular velocitysensor 85 is, for example, a sensor that detects the motion in theyawing direction perpendicular to the optical axis AZ. Examples ofangular velocity sensor 85 include a gyro sensor. FIG. 2 shows angularvelocity sensor 85 in only one direction, and the shake detectingsection in the pitching direction is omitted.

In this way, angular velocity sensor 85 incorporated in body shakedetecting section 30 has the function of detecting the motion of digitalsingle-lens reflex camera 1 caused by a shaking hand and othervibrations.

Body camera shake correcting section 76 is comprised of imaging sensor11 as part of imaging section 71, imaging sensor drive section 35 thatmoves imaging sensor 11 up, down, left and right within the planeperpendicular to the optical axis AZ of the imaging optical system L andcamera shake correction control section 31 that controls the drive ofimaging sensor drive section 35. Camera shake correction control section31 is comprised of amount-of-movement detecting section 37 that detectsthe actual amount of movement of imaging sensor 11 in imaging sensordrive section 35, shift control section 31 a that controls the operationof imaging sensor drive section 35 so that the amount of movementdetected by amount-of-movement detecting section 37 becomes the amountof drive control indicated by a control signal outputted from bodymicrocomputer 12 and D/A conversion section 36 that converts the controlsignal outputted from body microcomputer 12 to an analog signal. Shiftcontrol section 31 a and amount-of-movement detecting section 37 form afeedback control loop to drive and control imaging sensor drive section35 in body camera shake correcting section 76.

Furthermore, body microcomputer 12 is provided with control signalgeneration section 12 b that applies filtering, integration processing,phase compensation, gain adjustment and clipping processing to theoutput signal of angular velocity sensor 85 incorporated via A/Dconversion section 89, finds the amount of drive control of imagingsensor drive section 35 necessary for camera shake correction andoutputs the amount of drive control as a control signal. The controlsignal generated here is outputted to shift control section 31 a via D/Aconversion section 36 of camera shake correction control section 31.Shift control section 31 a controls the drive of imaging sensor drivesection 35 based on this control signal.

With such a configuration, imaging sensor 11 is shifted by imagingsensor drive section 35 so as to counterbalance the amount of shakedetected by body shake detecting section 30. This allows camera body 3to correct camera shake due to the shake of digital single-lens reflexcamera 1, making it possible to suppress the influence of the shake ofthe photographer's hand and so on and take good photographs.

Memory section 12 a in body microcomputer 12 stores data of the amountof shift from the center of the optical axis AZ of imaging sensor 11corresponding to the focal length of replacement lens 2 used upon camerashake correction, in addition to various programs, to control the driveof camera body 3. The correction range of a camera shake correctingapparatus using an imaging sensor generally has a certain relationshipwith the focal length of the attached replacement lens. That is,assuming the focal length of replacement lens 2 is f[m] and the angle bywhich digital single-lens reflex camera 1 shakes within a predeterminedtime (within the exposure time) due to vibration is θ[rad], the amountof movement ΔY[m] of the image on imaging sensor 11 is expressed byequation 1 below.ΔY=f×tan θ  (Equation 1)

Therefore, upon camera shake correction, by contrast, driving imagingsensor 11 and canceling out the amount of movement ΔY of this imageallows camera shake to be corrected. In other words, the maximumcorrectable angle θ that can be corrected through camera shakecorrection is determined by a variable range of individual camera bodycamera shake correcting apparatus 75.

Next, replacement lens camera shake correcting apparatus 82 will beexplained.

As shown in FIG. 6 and FIG. 7, replacement lens camera shake correctingapparatus 82 is an optical camera shake correcting apparatus and iscomprised of lens shake detecting section 21 that detects the shake ofdigital single-lens reflex camera 1 and lens camera shake correctingsection 83 that corrects camera shake according to the amount of shakedetected by lens shake detecting section 21.

Lens shake detecting section 21 is comprised of angular velocity sensor91 that detects the motion of digital single-lens reflex camera 1 itselfincluding the imaging optical system L, high pass filter (HPF) 92 thatremoves the DC drift component in unnecessary band components includedin the output of angular velocity sensor 91, low pass filter (LPF) 93that removes the sensor resonance frequency component and noisecomponent in unnecessary band components included in the output ofangular velocity sensor 91, amplifier 94 that adjusts the output signallevel of angular velocity sensor 91 and A/D conversion section 95 thatconverts the output signal of amplifier 94 to a digital signal. Examplesof angular velocity sensor 91 include a gyro sensor.

Lens camera shake correcting section 83 is comprised of shake correctionlens group 22 that constitutes part of the imaging optical system L,correction lens drive section 28 that moves shake correction lens group22 within a plane perpendicular to the optical axis AZ of the imagingoptical system L and camera shake correction control section 23 thatcontrols the operation of correction lens drive section 28 according tothe amount of shake detected by shake detecting section 21. The imagingoptical system L is not limited to the configuration of the opticalsystem above.

Camera shake correction control section 23 is comprised ofamount-of-movement detecting section 40 that detects the actual amountof movement of shake correction lens group 22 in correction lens drivesection 28, shift control section 23 a that controls the operation ofcorrection lens drive section 28 so that the amount of movement detectedby amount-of-movement detecting section 40 becomes the amount of drivecontrol indicated by a control signal outputted from lens microcomputer20 and D/A conversion section 46 that converts the control signaloutputted from lens microcomputer 20 to an analog signal. Shift controlsection 23 a and amount-of-movement detecting section 40 form a feedbackcontrol loop to drive and control correction lens drive section 28 inreplacement lens camera shake correcting apparatus 82.

With such a configuration, shake correction lens group 22 is shifted bycorrection lens drive section 28 so as to counterbalance the amount ofshake detected in lens shake detecting section 21, thereby correctingcamera shake.

Lens microcomputer 20 is provided with control signal generation section20 b that applies filtering, integration processing, phase compensation,gain adjustment and clipping processing to the output signal of angularvelocity sensor 91 incorporated via A/D conversion section 95, finds theamount of drive control of correction lens drive section 28 necessaryfor shake correction and outputs the amount of drive control as acontrol signal. The control signal generated here is outputted to shiftcontrol section 23 a via D/A conversion section 46. Camera shakecorrection control section 23 controls the drive of correction lensdrive section 28 based on this control signal. This allows replacementlens 2 to optically correct the camera shake produced by the shake ofdigital single-lens reflex camera 1, making it possible to suppress theinfluence of the shake of the photographer's hand and take goodphotographs.

Furthermore, memory section 20 a in lens microcomputer 20 stores dataindicating the focal length and the relationship between the distancefrom the subject and the amount of movement of focus lens group 24, anddata of the amount of shift from the center of the optical axis AZ ofshake correction lens group 22 according to the focal length and so on,in addition to various programs to control the drive of replacement lens2. As for the amount of shift of shake correction lens group 22,information about the maximum correctable angle θ that can be correctedby replacement lens 2 based on the amount of movement ΔY of the imageexpressed by equation 1 above is stored in memory section 20 a.Furthermore, memory section 20 a also stores information about powerconsumption necessary to drive shake correction lens group 22 uponcamera shake correction.

As described above, digital single-lens reflex camera 1 according to thepresent embodiment is a digital single-lens reflex camera having monitorphotographing mode with a camera shake correcting function and iscomprised of camera body 3 and replacement lens 2 detachably mounted incamera body 3. Features in the configuration are summarized as follows.Monitor photographing mode will be described later.

Camera body 3 includes imaging sensor 11, quick return mirror 4, afocusing means that performs focus detection based on a contrast schemeusing imaging sensor 11, motion detecting section 100 that detects thesubject speed from the image on imaging sensor 11 and a control meansthat performs camera shake correction according to the subject speeddetected by motion detecting section 100, in which the focusing means,motion detecting section 100 and the control means start operating whilequick return mirror 4 is retracted from the optical axis. The controlsection above can be any means as long as it works as a control means tocorrect camera shake. Furthermore, the camera shake correction hereincludes not only a case where some lenses of the imaging optical systemL or imaging sensor 11 are/is moved to optically correct shake but alsoa case where camera shake is corrected through signal processing or alsoa combination of these cases. With digital single-lens reflex camera 1,such a control means, focusing means and motion detecting section 100enter operation mode while quick return mirror 4 is retracted from theoptical axis. The focusing means is realized by body microcomputer 12that calculates the AF evaluation value and so on (which will bedescribed later).

Furthermore, digital single-lens reflex camera 1 has a camera shakecorrecting section, which is mounted in at least one of camera body 3and replacement lens 2 to correct the shake of the optical image due tothe motion of camera body 3. To be more specific, digital single-lensreflex camera 1 has camera body camera shake correcting apparatus 75 onthe camera body 3 side and replacement lens camera shake correctingapparatus 82 on the replacement lens 2 side. The control means aboveincreases, if the subject speed detected by motion detecting section 100is equal to or above a threshold, the amplification factor of the imageor shortens the exposure time, or controls, if the subject speeddetected by motion detecting section 100 is below the threshold, camerabody camera shake correcting apparatus 75 or replacement lens camerashake correcting apparatus 82 to optically execute camera shakecorrection. As for increasing the amplification factor of the image andshortening the exposure time, either one or both may be done.

The operation of digital single-lens reflex camera 1 configured as shownabove will be explained below.

First, the photographing operation of digital single-lens reflex camera1 will be explained.

FIG. 8 and FIG. 9 are conceptual diagrams of digital single-lens reflexcamera 1 at the time of taking a photograph, and, particularly, FIG. 8is a conceptual diagram illustrating finder photographing mode, and FIG.9 is a conceptual diagram illustrating monitor photographing mode.

[Operation Before Imaging]

As shown in FIG. 8 and FIG. 9, light from the subject (not shown) passesreplacement lens 2 and is incident on main mirror 4 a, which is asemitransparent mirror of quick return mirror 4. Part of the lightincident upon main mirror 4 a is reflected and is incident on finderscreen 6, while the rest of the light passes quick return mirror 4 andis incident on sub-mirror 4 b (not shown). Light incident upon finderscreen 6 forms an image of the subject. This subject image is convertedby pentaprism 7 to an erect image and is incident on eyepiece 8. Thisallows the photographer to see the erect image of the subject via findereyepiece window 9. On the other hand, the light incident upon sub-mirror4 b (not shown) is reflected here and is incident on focus detectingunit 5 (not shown).

[Finder Photographing Mode and Monitor Photographing Mode]

This digital single-lens reflex camera 1 has two photographing modesusing different subject checking methods, that is, finder photographingmode and monitor photographing mode. Here, “finder photographing mode”is a photographing mode in which the photographer takes a photograph byobserving the subject from finder eyepiece window 9, and is normalphotographing mode for a conventional single-lens reflex camera. On theother hand, “monitor photographing mode” is a photographing mode inwhich the photographer takes a photograph while viewing the subject as aphotographed image of display section 16 and is one of features of thepresent embodiment.

In finder photographing mode, as shown in FIG. 8, quick return mirror 4is placed in a predetermined position in the optical axis AZ, thesubject light is guided to finder optical system 19, and thephotographer can therefore observe the subject image from findereyepiece window 9. When a photograph is actually taken, quick returnmirror 4 is flipped up outside the optical axis AZ, shutter unit 10 isopened, and an image of the subject is formed on the imaging plane ofimaging sensor 11.

On the other hand, in monitor photographing mode, as shown in FIG. 9,quick return mirror 4 is retracted from within the optical axis AZ.Therefore, an image of the subject via imaging sensor 11, that is, aso-called “through-the-lens image” is displayed on display section 16.

[Operation of Finder Photographing Mode]

Next, the photographing operation of digital single-lens reflex camera 1will be explained. First, a drive sequence in finder photographing modein which the photographer takes a photograph by looking into findereyepiece window 9 will be explained using FIG. 1 to FIG. 4 and FIG. 8.

When taking a photograph in finder photographing mode, the photographersets finder photographing mode by operating photographing mode switchingbutton 58 provided on the back of casing 3 a.

After that, a half-press operation of shutter operation section 53 bythe photographer causes power to be supplied to body microcomputer 12and various units in digital single-lens reflex camera 1. Bodymicrocomputer 12 in digital single-lens reflex camera 1 started uponpower-up receives various types of lens data from lens microcomputer 20in replacement lens 2 likewise started upon power-up via lens mount 80and body mount 81 and saves the lens data in built-in memory section 12a. Next, body microcomputer 12 acquires the amount of defocus(hereinafter referred to as “the amount of Df”) from focus detectingunit 5 and commands lens microcomputer 20 to drive focus lens group 24for the amount of Df. Lens microcomputer 20 then controls focus lensgroup drive control section 25 to operate focus lens group 24 for theamount of Df. Repeating focus detection and the drive of focus lensgroup 24 in this way causes the amount of Df to decrease. When theamount of Df falls to or below a predetermined amount, bodymicrocomputer 12 judges that focus is achieved, and stops the drive offocus lens group 24.

After that, when the photographer fully presses shutter operationsection 53, body microcomputer 12 commands lens microcomputer 20 to setthe aperture value to the aperture value calculated based on the outputfrom a photometric sensor (not shown). Lens microcomputer 20 thencontrols aperture drive control section 27 to narrow the aperture ofaperture section 26 to the aperture value commanded. At the same timewith the command regarding the aperture value, body microcomputer 12causes quick return mirror control section 60 to retract quick returnmirror 4 from within the optical axis AZ. After quick return mirror 4has been retracted, imaging sensor control section 13 commands the driveof imaging sensor 11 and shutter control section 14 commands theoperation of shutter unit 10. Shutter control section 14 exposes imagingsensor 11 for a period of time corresponding to the shutter speedcalculated based on the output from the photometric sensor above.

After the exposure is finished, the image data read from imaging sensor11 by imaging sensor control section 13 is subjected to predeterminedimage processing and displayed on display section 16 as a photographedimage. On the other hand, the image data read from imaging sensor 11 andsubjected to predetermined image processing is written to imagereading/recording section 18 as image data. Furthermore, aftercompletion of the exposure, quick return mirror 4 and shutter unit 10are reset to their initial positions. Furthermore, body microcomputer 12commands lens microcomputer 20 to reset the aperture of aperture section26 in an open position and lens microcomputer 20 issues a reset commandto each unit. After the resetting is completed, lens microcomputer 20informs body microcomputer 12 of the completion of reset. Bodymicrocomputer 12 waits for information indicating completion ofresetting from lens microcomputer 20 and completion of a series ofprocesses after the exposure, and, upon confirming that the shutteroperation section 53 is not set in a pressed position, finishes thedrive sequence.

[Operation of Monitor Photographing Mode]

Next, a drive sequence in monitor photographing mode in which thephotographer takes a photograph using display section 16 will beexplained using FIG. 1 to FIG. 4 and FIG. 9.

When taking a photograph using display section 16, the photographer setsmonitor photographing mode by operating photographing mode switchingbutton 58. When monitor photographing mode is set, body microcomputer 12causes quick return mirror 4 to retract from within the optical axis AZ.This allows the light from the subject to reach imaging sensor 11, sothat imaging sensor 11 can convert the light from the subject, whoseimage is formed on imaging sensor 11, to image data, and acquire andoutput the image of the subject as image data. The image data read fromimaging sensor 11 by imaging sensor control section 13 is subjected topredetermined image processing and then displayed on display section 16as a photographed image. Thus, by causing display section 16 to displaya photographed image, the photographer can chase the subject withoutlooking into finder eyepiece window 9.

In this monitor photographing mode, instead of a phase differencedetection scheme using focus detecting unit 5, contrast type autofocusbased on image data generated by imaging sensor 11 is used as a focusingmethod thereof. Using the contrast scheme as the autofocus operationscheme in monitor photographing mode using display section 16, it ispossible to realize accurate focus operations as the digital single-lensreflex camera. This is because in this monitor photographing mode, imagedata is generated by imaging sensor 11 on a regular basis, and it istherefore easy to perform an autofocus operation based on the contrastscheme using that image data.

Next, the autofocus operation using the contrast scheme will beexplained.

When performing an autofocus operation based on the contrast scheme,body microcomputer 12 requests contrast AF data from lens microcomputer20. Contrast AF data refers to data required in the autofocus operationunder the contrast scheme, and examples of contrast AF data include thefocus drive speed, the amount of focus shift, the magnification of theimage and information about the necessity for contrast AF.

Body microcomputer 12 regularly generates vertical synchronizationsignals. Furthermore, in parallel with this, body microcomputer 12generates an exposure synchronization signal based on a verticalsynchronization signal. Thus, body microcomputer 12 can generate anexposure synchronization signal based on a vertical synchronizationsignal because body microcomputer 12 knows in advance the exposure starttiming and exposure end timing with reference to the verticalsynchronization signal. Body microcomputer 12 outputs the verticalsynchronization signal to a timing generator (not shown) and outputs theexposure synchronization signal to lens microcomputer 20. Lensmicrocomputer 20 acquires position information of focus lens group 24via focus lens group drive control section 25 in synchronization withthe exposure synchronization signal.

Imaging sensor control section 13 regularly generates a reading signalof imaging sensor 11 and electronic shutter drive signal based on thevertical synchronization signal. Imaging sensor control section 13drives imaging sensor 11 based on the reading signal and electronicshutter drive signal. That is, imaging sensor 11 reads out pixel datagenerated by many photoelectric conversion devices (not shown) existingin imaging sensor 11 to the vertical transfer section (not shown)according to the reading signal.

Next, through a half-press operation of shutter operation section 53 bythe photographer, body microcomputer 12 of digital single-lens reflexcamera 1 receives various types of lens data from lens microcomputer 20in replacement lens 2 via lens mount 80 and body mount 81 and saves thelens data in built-in memory section 12 a. Furthermore, bodymicrocomputer 12 sends an autofocus start command to lens microcomputer20. The autofocus start command when shutter operation section 53 ishalf-pressed is a command indicating that an autofocus operation basedon a contrast scheme should be started. Upon receiving this command,lens microcomputer 20 drives and controls focus lens group 24 in adirection parallel to the optical axis AZ. Furthermore, bodymicrocomputer 12 calculates an evaluation value for autofocus operation(hereinafter referred to as “AF evaluation value”) based on the receivedimage data. To be more specific, as the method of calculating an AFevaluation value, for example, a method is known, whereby a brightnesssignal is obtained from image data generated by imaging sensor 11, andan AF evaluation value is found by adding up the high frequencycomponents of the brightness signal within the screen. The calculated AFevaluation value is associated with the exposure synchronization signaland saved in, for example, a DRAM (not shown) constituting memorysection 12 a. The lens position information acquired from lensmicrocomputer 20 is also associated with the exposure synchronizationsignal. Therefore, body microcomputer 12 can save the AF evaluationvalue in association with the lens position information.

Next, body microcomputer 12 finds a contrast peak based on the AFevaluation value saved in the DRAM above and monitors whether or not afocus point has been successfully extracted. To be more specific, bodymicrocomputer 12 extracts the position of focus lens group 24 where theAF evaluation value becomes the maximum value as a focus point. As thislens drive scheme, a hill-climbing method is generally known.

Furthermore, in this state, digital single-lens reflex camera 1 displaysthe image indicated by image data generated by imaging sensor 11 ondisplay section 16 as a through-the-lens image. Since thisthrough-the-lens image is displayed on display section 16 as videoimage, the photographer can determine the composition to pick up a stillimage or video image by looking into display section 16.

After that, when the photographer fully presses shutter operationsection 53, body microcomputer 12 commands lens microcomputer 20 toadopt the aperture value calculated based on the output of imagingsensor 11 as the aperture value. Lens microcomputer 20 then controlsaperture drive control section 27 to narrow the aperture of aperturesection 26 to the aperture value commanded. Furthermore, imaging sensorcontrol section 13 commands the drive of imaging sensor 11 and shuttercontrol section 14 commands the operation of shutter unit 10. Shuttercontrol section 14 exposes imaging sensor 11 for a period of timecorresponding to the shutter speed calculated based on the output ofimaging sensor 11.

After the exposure is finished, the image data read from imaging sensor11 by imaging sensor control section 13 is subjected to predeterminedimage processing and then displayed on display section 16 as aphotographed image. Furthermore, the image data read from imaging sensor11 and subjected to predetermined image processing is written to imagereading/recording section 18 as image data. Furthermore, aftercompletion of the exposure, since quick return mirror 4 is located in aposition retracted from within the optical axis AZ, the photographer cancontinue viewing the subject in monitor photographing mode as aphotographed image on display section 16.

When canceling monitor photographing mode, the photographer operatesphotographing mode switching button 58 to switch the mode to finderphotographing mode in which a photograph is taken by looking into findereyepiece window 9. When the mode is switched to finder photographingmode, quick return mirror 4 is returned to a predetermined positionwithin the optical axis AZ. Furthermore, also when power to digitalsingle-lens reflex camera 1 or camera body 3 is cut, quick return mirror4 is returned to the predetermined position within the optical axis AZ.

[Second Configuration of Camera Body]

FIG. 10 is a block diagram showing a modification example of the digitalsingle-lens reflex camera shown in FIG. 1. In FIG. 10, the samecomponents as those in FIG. 1 are assigned the same reference numerals.

In FIG. 10, digital single-lens reflex camera 1 a is a replacement lenstype digital single-lens reflex camera and is roughly comprised ofcamera body 3 a having main functions of digital single-lens reflexcamera 1 a and replacement lens 2 detachably mounted in camera body 3 a.Replacement lens 2 is attached to body mount 81 provided in the front ofcamera body 3 a via lens mount 80 provided in the rearmost part.

A modification in camera body 3 a shown in FIG. 10 made to camera body 3shown in FIG. 1 is in that quick return mirror 4 that guides incidentlight in camera body 3 shown in FIG. 1 to finder optical system 19 andfocus detecting unit 5 is removed from imaging section 71 a andelectronic finder section 90 such as a liquid crystal finder is providedinstead. As in the case of display section 16, by causing electronicfinder section 90 to display an image signal recorded in imagereading/recording section 18 or buffer memory 69 as a visible imagebased on a command from image display control section 15, thephotographer can observe the subject image through finder eyepiecewindow 9.

Camera body 3 a can be made thinner by removing finder optical system 19and quick return mirror 4. Moreover, since a “lens back,” which is thedistance from the hindmost lens of replacement lens 2 to imaging sensor11, can be shortened, it is possible to reduce the size of replacementlens 2.

Furthermore, camera body 3 a in FIG. 10 can realize accurate focusoperations by always using a contrast scheme based on image datagenerated by imaging sensor 11 as a focus detection method thereof.Furthermore, given that the operation of opening/closing quick returnmirror 4 is no longer necessary, it is possible to make the focusoperation faster and more silent, and furthermore support not onlyconventional still-image photographing but also video photographing.

The following explanations are explanations of operation applicable toboth digital single-lens reflex camera 1 shown in FIG. 1 and digitalsingle-lens reflex camera 1 a shown in FIG. 10. Therefore, the operationof digital single-lens reflex camera 1 shown in FIG. 1 will be explainedas a representative example below.

[Selection Operation when Replacement Lens is Mounted in Camera Body]

Next, a more specific camera shake correcting apparatus selectionoperation when replacement lens 2 is mounted on camera body 3 will beexplained.

FIG. 11 is a flowchart showing a sequence regarding a selectionoperation of a camera shake correcting apparatus of the presentembodiment.

In the present embodiment, suppose when both replacement lens 2 andcamera body 3 are mounted with a camera shake correcting apparatus,replacement lens camera shake correcting apparatus 82 on the replacementlens 2 side is selected preferentially. This is because the camera shakecorrection by replacement lens camera shake correcting apparatus 82 isconsidered to be advantageous over the camera shake correction by camerabody camera shake correcting apparatus 75 for the following reasons.That is, this is based on the following reasons: (1) shake correction ismore effective if carried out on the replacement lens 2 side, which isthe source of shake (especially the telephoto lens); and (2) given thatreplacement lens 2 is designed for dedicated use and camera body 3 isdesigned for general use, shake correction, if carried out on the sideof replacement lens 2 for dedicated use, provides optimal design forshake correction. However, the advantages and disadvantages of camerashake correction on the camera body 3 side (generally, correction bymoving the CCD in the opposite direction to the shake direction) andcamera shake correction on the replacement lens 2 side depend on designspecifications and so on, and cannot be defined in a fixed manner.Furthermore, when the camera shake correcting apparatus is mounted onone of replacement lens 2 and camera body 3, use of the camera shakecorrecting apparatus mounted on the side with the camera shakecorrecting apparatus will be assumed in the following explanations.

First in step S1, body microcomputer 12 decides whether or notreplacement lens 2 is attached. When replacement lens 2 is attached tocamera body 3, body microcomputer 12 of camera body 3 detects theattachment of replacement lens 2.

In step S2, body microcomputer 12 acquires data in replacement lens 2.

In step S3, body microcomputer 12 decides whether or not camera shakecorrecting apparatus 82 is mounted in replacement lens 2 attached. Afterreplacement lens 2 is attached, body microcomputer 12 acquiresinformation as to whether or not replacement lens camera shakecorrecting apparatus 82 is mounted in replacement lens 2 from memorysection 20 a of lens microcomputer 20 in replacement lens 2. Theinformation includes information as to whether or not the camera shakecorrecting apparatus is mounted, and body microcomputer 12 decideswhether or not replacement lens camera shake correcting apparatus 82 ismounted in replacement lens 2 based on this information.

If, as a result of this decision, replacement lens camera shakecorrecting apparatus 82 is mounted in replacement lens 2, the step movesto step S4. On the other hand, if replacement lens camera shakecorrecting apparatus 82 is not mounted in replacement lens 2, the stepmoves to step S6.

In step S4, body microcomputer 12 stops camera body camera shakecorrecting apparatus 75 in camera body 3. As described above, if camerashake correcting apparatus 82 is mounted in replacement lens 2, this isintended to stop driving camera body camera shake correcting apparatus75 on the camera body 3 side to give priority to replacement lens camerashake correcting apparatus 82.

In step S5, body microcomputer 12 starts driving replacement lens camerashake correcting apparatus 82 and finishes this sequence, therebyplacing digital single-lens reflex camera 1 in a state ready to takephotographs.

On the other hand, in step S6, to which the step moves when replacementlens camera shake correcting apparatus 82 is not mounted in replacementlens 2 as a result of the decision in step S3, body microcomputer 12decides whether or not camera body camera shake correcting apparatus 75is mounted in camera body 3.

If, as a result of this decision, camera body camera shake correctionapparatus 75 is mounted in camera body 3, the step moves to step S7,and, on the other hand, when camera body camera shake correctionapparatus 75 is not mounted in camera body 3, the step moves to step S8.

In step S7, body microcomputer 12 starts driving camera body camerashake correcting apparatus 75 and finishes this sequence, therebyplacing digital single-lens reflex camera 1 in a state ready to takephotographs.

On the other hand, in step S8, to which the step moves if as a result ofthe decision in step S6 camera body camera shake correcting apparatus 75is not mounted in camera body 3, body microcomputer 12 memorizes, in itsbuilt-in memory section 12 a, the fact that camera shake correctingapparatus is not mounted in replacement lens 2 or camera body 3, anddigital single-lens reflex camera 1 shifts to a state in whichphotographs can be taken.

As described above, digital single-lens reflex camera 1 automaticallydecides whether a camera shake correcting apparatus is mounted in one orboth of replacement lens 2 and camera body 3, and camera shakecorrecting apparatus 82 set up in advance in replacement lens 2 isdriven preferentially, thereby allowing the camera shake correctingapparatus to operate normally without entailing malfunctions. Thephotographer may be allowed to select whether to use camera shakecorrecting apparatus 82 in replacement lens 2 or camera shake correctingapparatus 75 in camera body 3.

[Operation when Photograph is Taken]

Next, the operation of digital single-lens reflex camera 1 with thecamera shake correcting function and photographing sensitivity changingfunction will be explained.

First, the photographing mode which is selectable in digital single-lensreflex camera 1 will be explained. The photographing mode includes“continuous shooting mode,” in which shutter unit 10 is operated at timeintervals of 0.3 seconds and photographs are taken a plurality of times(two or three or more times), “sensitivity increasing & camera shakecorrection automatic selection mode,” “sensitivity increasing mode” and“camera shake correction mode,” and so on (which will be describedlater), and the photographer can select a desired photographing mode.When the photographing mode is selected, body microcomputer 12 controlsvarious types of control section according to the respectivephotographing modes.

FIG. 12 illustrates a display example of a photographing mode selectingscreen displayed on display section 16. The photographing mode selectingscreen can be displayed on display section 16 by the photographeroperating MENU setting operation section 56 or operation cross key 55.As shown in FIG. 12, the photographing mode includes sensitivityincreasing & camera shake correction automatic selection mode,sensitivity increasing mode, camera shake correction mode and mode OFF,and the photographer can set the desired photographing mode by selectingicon 190, 191, 192 or 193. Although FIG. 12 displays only characteristicphotographing mode selection icons in the present embodiment, thepresent invention is not limited to these and other photographing modeselection icons such as the above-described continuous shooting mode mayalso be displayed.

When sensitivity increasing mode selection icon 191 is selected,photographing sensitivity higher than normal photographing sensitivityis selected (“sensitivity increasing mode”). That is, digital signalamplification section 110 amplifies an image signal by a predeterminedgain according to a command from body microcomputer 12. This makes itpossible to shorten the exposure time and take a photograph at a fastershutter speed, thereby reducing the influence of camera shake.

When camera shake correction mode selection icon 192 is selected, thecamera shake correcting function operates (“camera shake correctionmode”). That is, digital single-lens reflex camera 1 drives one ofcamera body camera shake correcting apparatus 75 in camera body 3 andreplacement lens camera shake correcting apparatus 82 in replacementlens 2 according to a command from body microcomputer 12, moves imagingsensor 11 or shake correction lens group 22 in two directions (up, down,left and right) within the plane perpendicular to the optical axis AZand reduces camera shake.

When sensitivity increasing & camera shake correction automaticselection mode icon 190 is selected, body microcomputer 12 automaticallyswitches the photographing mode to one of sensitivity increasing modeand camera shake correction mode according to the speed at which thesubject moves. This causes photographing sensitivity to be set to highsensitivity when the subject moves at such a high speed to cause subjectshake, whereas, when the subject moves at such a low speed subject shakeis not caused, the camera shake correcting function that reduces camerashake operates. According to the present embodiment, when sensitivityincreasing & camera shake correction automatic selection mode icon 190is selected, the mode is automatically shifted to monitor photographingmode, which is a feature of the present embodiment. That is, bodymicrocomputer 12 retracts quick return mirror 4 from within the opticalaxis AZ and automatically changes the focus detection scheme to acontrast scheme based on image data generated by imaging sensor 11.Furthermore, as a focus scheme, face-first focus mode may be adopted inwhich focus is set on the face of the subject preferentially, so thatwhen the photographer selects face-first focus mode, the step moves tosensitivity increasing & camera shake correction automatic selectionmode and automatically selects one of sensitivity increasing mode andcamera shake correction mode.

When mode OFF selection icon 193 is selected, the above-describedphotographing sensitivity increasing function and camera shakecorrecting function do not operate and regular photographing in normalmode is possible.

Next, photographing process when sensitivity increasing & camera shakecorrection automatic selection mode is selected will be explained usinga flowchart in FIG. 13.

FIG. 13 is a flowchart illustrating the steps of photographing processby digital single-lens reflex camera 1, which are executed by bodymicrocomputer 12. This flowchart is started when, for example, powerswitch 52 of digital single-lens reflex camera 1 is set to the ON side.

In step S11, when the photographer operates MENU setting operationsection 56 provided on the back of casing 3 a of camera body 3, bodymicrocomputer 12 makes display section 16 display an icon showing a listof photographing modes. When the photographer selects sensitivityincreasing & camera shake correction automatic selection mode icon 190from among the photographing mode selection icons displayed on displaysection 16, the step moves to S12 and camera shake correction modestarts.

In step S12, body microcomputer 12 switches the photographing mode tocamera shake correction mode and makes one of camera shake correctingapparatus 75 in camera body 3 and camera shake correcting apparatus 82in replacement lens 2 operate. Which camera shake correcting apparatusto be used is determined based on the method shown in the flowchart inFIG. 11.

In step S13, when the photographer half-presses shutter operationsection 53, body microcomputer 12 recognizes that shutter operationsection 53 is half-pressed, and moves the step to step S14.

In step S14, the face of the subject is detected. Face detectionprocessing is performed by face detecting section 120. As the facedetection method, there is a method of detecting contour informationfrom the photographed image and detecting whether or not there arefeatures (e.g. eyes, nose, mouth and so on) within the detected contour.If the detected contour shows features, face detection section 120decides that there is a face.

FIG. 14 shows a display example where an image photographed in camerashake correction mode of digital single-lens reflex camera 1 isdisplayed on display section 16.

When face detection is performed, as shown in FIG. 14, an AF area frameFa is set in a predetermined position on the photographing screen whereface detection processing is performed on person A (the subject). As forthe photographing subject, a specific subject may be set preferentiallyamong a plurality of subjects. Furthermore, when a face cannot bedetected as a subject, sensitivity increasing & camera shake correctionautomatic selection mode is exited and photographs continue being takenin normal camera shake correction mode.

In step S15, the motion of the face of the subject is detected. In facemotion detection processing, motion detecting section 100 detects themotion of the subject to be photographed by chasing the representativepoints in a photographed image, and outputs a motion vector.Furthermore, for example, photometric processing and distance measuringprocessing are performed at the same time with the motion detectionprocessing. In the photometric processing, digital signal processingsection 68 calculates an exposure value based on an image signaloutputted from imaging sensor 11. Body microcomputer 12 automaticallysets an adequate shutter speed based on the calculated exposure value.Furthermore, in the distance measuring processing, focus lens groupdrive control section 25 moves focus lens group 24 in the optical axisAZ direction and adjusts focus so that the contrast value of the imagesignal shows a peak.

Furthermore, upon detecting the motion of the face of the subject,motion detection can be performed with reduced influence of camerashake, because camera shake correction is performed, thus improving theaccuracy of motion detection. That is, it is possible to distinguishwhether the motion of the image in imaging sensor 11 is caused by themotion of the subject or by the influence of the motion of the camerabody due to the shake of the photographer's hand and so on. The motionof the subject is not limited to the motion of the subject's face aloneand can be judged from the motion of the entire body of the subject.

In step S16, body microcomputer 12 calculates the moving speed Vh of theface of the subject per unit time from the motion vector detected bymotion detecting section 100.

In step S17, the moving speed Vh is determined. To be more specific, apredetermined value A is registered in advance in digital single-lensreflex camera 1, and body microcomputer 12 compares the moving speed Vhwith the predetermined value A. Here, this predetermined value Arepresents a threshold at which subject shake occurs and may be a valuespecific to digital single-lens reflex camera 1 or may be arbitrarilyset by the photographer. For example, when a flash is used, shutterspeed can be made faster, so that photographing sensitivity does notincrease more than necessary by increasing the threshold. On the otherhand, when taking a photograph of a child or pet likely to suddenly moveafter the subject speed is calculated and before the subject isphotographed, such a method may be used that digital single-lens reflexcamera 1 may be provided with child photographing mode or petphotographing mode separately so that, when the photographer selects themode, the threshold is reduced to increase photographing sensitivitypreferentially. On the other hand, when taking a photograph of a nightview or when taking a photograph in a dark room, if the distance to thesubject is too far for flash light to reach, it is also possible toreduce the threshold and increase photographing sensitivitypreferentially. Furthermore, the threshold may be made variableaccording to image quality set when taking a photograph. For example,when taking photographs in the highest image quality (e.g. RAW fileformat (not compressed)), the threshold is increased to avoid imagequality degradation due to increase of photographing sensitivity, and,when taking photographs in standard image quality, priority may be givento increasing photographing sensitivity by reducing the threshold.

The present embodiment is characterized in that the above-describedthreshold A is not a fixed value but can be a plurality of thresholdsA1, A2, . . . , and the thresholds A1, A2, . . . , are set (selected)adaptively according to the combination of camera shake correctingapparatuses of replacement lens 2 and camera body 3. Here, theabove-described threshold A normally has two values, threshold A1 fornormal photographing mode and threshold A2 for high sensitivitypreferential photographing mode (A1<A2). In this step S17, according tothe combination of camera shake correcting apparatuses of replacementlens 2 and camera body 3, when, for example, in the case of acombination in high sensitivity preferential photographing mode,sensitivity increasing mode is started earlier by switching threshold A1for normal photographing mode to threshold A2 for high sensitivitypreferential photographing mode having a lower threshold (see FIG. 15,which will be described later).

When the amount of movement ΔY of an image on imaging sensor 11expressed by equation 1 above increases, that is, when the focal lengthf of replacement lens 2 increases or the angle θ by which digitalsingle-lens reflex camera 1 shakes increases, camera body camera shakecorrecting apparatus 75 normally has following defects (1) and (2)compared to the performance of camera shake correcting apparatus 82mounted on replacement lens 2.

(1) If the amount of movement ΔY of an image on imaging sensor 11exceeds, for example, 1 mm, the amount of drive of imaging sensor drivesection 35 that drives imaging sensor 11 increases, and consequently thesize of body camera shake correcting section 76 itself increases, whichleads to an increase in the size of camera body 3.

(2) An increase in the amount of movement of imaging sensor 11 leads todeterioration of the optical performance of the subject image in theperiphery of imaging sensor 11 such as a decrease in relativeillumination.

Therefore, when the focal length f of replacement lens 2 is large, it ispreferable to use camera shake correcting apparatus 82 for replacementlens 2 designed optimally to suit long focal length. Furthermore, evenwhen angle θ by which digital single-lens reflex camera 1 shakes islarge, it is preferable to use camera shake correcting apparatus 82 forreplacement lens 2 designed optimally by taking into account decrease inrelative illumination and so on.

Therefore, the present embodiment adopts a system configuration ofchanging threshold A depending on whether or not camera shake correctingapparatus 82 is mounted on replacement lens 2 and the focal length f ofreplacement lens 2.

FIG. 15 illustrates the relationship between a combination of camerashake correcting apparatuses in the replacement lens and the camera bodyof digital single-lens reflex camera 1, and threshold A.

Digital single-lens reflex camera 1 of the present embodiment has acamera shake correcting apparatus in at least one of camera body 3 andreplacement lens 2 used in combination. Therefore, depending on thepresence/absence of the camera shake correcting apparatus on the camerabody side and on the replacement lens side, the following threephotographing modes are set, that is, (1) normal photographing mode, (2)high sensitivity preferential photographing mode and (3) sensitivityincreasing mode. Furthermore, when there is no camera shake correctingapparatus on the replacement lens side, threshold A of the photographingmode is changed according to the focal length of replacement lens 2 forthe above-described reason. Here, depending on whether the focal lengthof replacement lens 2 is less than 300 mm or equal to or above 300 mm,normal photographing mode (threshold A1) or high sensitivitypreferential photographing mode (threshold A2) (where A1>A2) is set.This is merely an example and two or more thresholds may be provideddepending on the focal length set value or the focal length ofreplacement lens 2.

As shown in FIG. 15, when neither the camera body side nor thereplacement lens side is provided with any camera shake correctingapparatus, sensitivity increasing mode is set regardless of whether thefocal length of replacement lens 2 is below 300 mm or equal to or above300 mm (see (a) and (b) in FIG. 15). When neither the camera body sidenor the replacement lens side is provided with any camera shakecorrecting apparatus, by setting high sensitivity for photographingsensitivity, it is possible to shorten the exposure time, take aphotograph at a faster shutter speed and thereby reduce the influence ofcamera shake.

Furthermore, if a camera shake correcting apparatus is provided oneither the camera body side or the replacement lens side, normalphotographing mode (threshold A1) is basically set (see (c), (d) and (f)in FIG. 15). More specifically, if camera shake correcting apparatus 82is provided on the replacement lens side, normal photographing mode(threshold A1) is set regardless of whether or not there is camera shakecorrecting apparatus 75 on the camera body side (see (c) and (f) in FIG.15). If camera shake correcting apparatus 75 is provided on the camerabody side, one of normal photographing mode (threshold A1) and highsensitivity preferential photographing mode (threshold A2) is setdepending on the presence/absence of camera shake correcting apparatus82 on the replacement lens side. To be more specific, when the camerabody side is provided with camera shake correcting apparatus 75, normalphotographing mode (threshold A1) is set if camera shake correctingapparatus 82 is provided on the replacement lens side (see (f) in FIG.15) or even if camera shake correcting apparatus 82 is not provided onthe replacement lens side if the focal length of replacement lens 2 isbelow 300 mm (see (d) in FIG. 15). It should be noted that althoughnormal photographing mode (threshold A1) in (c), (d) and (f) in FIG. 15is the same normal photographing mode (threshold A1), normalphotographing mode in (c) and (f) in FIG. 15 applies to the replacementlens side and normal photographing mode in (d) in FIG. 15 applies to thecamera body side. In normal photographing mode, since photographingsensitivity is not increased more than necessary while camera shake isbeing effectively prevented, photographing of high image quality is madepossible.

Furthermore, if camera shake correcting apparatus 75 is provided on thecamera body side, if camera shake correcting apparatus 82 is provided onthe replacement lens side and the focal length of replacement lens 2 isequal to or above 300 mm (see (e) in FIG. 15), high sensitivitypreferential photographing mode (threshold A2) is set. In highsensitivity preferential photographing mode, the mode is shifted tosensitivity increasing mode earlier than in normal photographing modeand it is thereby possible to reduce the influence of camera shake.

Here, if camera shake correcting apparatuses are provided on both thecamera body side and the replacement lens side, as shown in theflowchart above in FIG. 11, body microcomputer 12 gives higher priorityto replacement lens camera shake correcting apparatus 82 and thereforestops driving camera shake correcting apparatus 75 on the camera bodyside. This is the case of normal photographing mode (threshold A1) in(f) in FIG. 15. Furthermore, if camera shake correcting apparatus 75 isprovided on the camera body side and camera shake correcting apparatus82 is not provided on the replacement lens side, normal photographingmode (threshold A1) or high sensitivity preferential photographing mode(threshold A2) is set depending on whether the focal length ofreplacement lens 2 is below 300 mm or equal to or above 300 mm in camerashake correcting apparatus 75 on the camera body side.

FIG. 16 illustrates the moving speed Vh of the subject and switching ofphotographing sensitivity S when a photograph is taken according tothreshold A. There are two types of threshold A, A1 and A2.

(1) In normal photographing mode (threshold A1), when the subject speedexceeds V2, sensitivity is increase gradually according to the subjectspeed.

In this case, irrespective of whether or not camera shake correctingapparatus 75 is mounted on camera body 3, combinations of thepresence/absence of camera shake correcting apparatuses in replacementlens 2 and camera body 3 correspond to: when replacement lens 2 ismounted with camera shake correcting apparatus 82 (see (c) and (f) inFIG. 15); and when replacement lens 2 is not mounted with camera shakecorrecting apparatus 82, the focal length f is below 300 mm and camerabody 3 is mounted with camera shake correcting apparatus 75 (see (d) inFIG. 15).

(2) In high sensitivity preferential photographing mode (threshold A2),when the subject speed exceeds V1, sensitivity is increase graduallyaccording to the subject speed.

In this case, combinations of the presence/absence of camera shakecorrecting apparatuses in replacement lens 2 and camera body 3correspond to: when replacement lens 2 is not mounted with camera shakecorrecting apparatus 82, the focal length f is equal to or above 300 mmand camera body 3 is mounted with camera shake correcting apparatus 75(see (e) in FIG. 15).

(3) In case of sensitivity increasing mode (sensitivity increasing modeselection icon 191 shown in FIG. 12)

In this case, combinations of the presence/absence of camera shakecorrecting apparatuses in replacement lens 2 and camera body 3correspond to: when none of replacement lens 2 or camera body 3 ismounted with any camera shake correcting apparatus (see (a) and (b) inFIG. 15).

These three modes are selectable by the photographer using MENU settingoperation section 56 of digital single-lens reflex camera 1. However, insensitivity increasing & camera shake correction automatic selectionmode, when the subject is moving fast, threshold A1 for normalphotographing mode is switched to threshold A2 for high sensitivitypreferential photographing mode with a lower threshold using acombination of replacement lens 2 and camera body 3. That is, whenthreshold A1 for normal photographing mode is used, it is not until thesubject speed reaches V2 that photographing sensitivity becomes S3,whereas, when threshold A2 for high sensitivity preferentialphotographing mode is used, photographing sensitivity becomes S2 whenthe subject speed reaches V1 and becomes S3 when the subject speedreaches V2.

Thus, according to the present embodiment, when a photograph is takenusing a combination of replacement lens 2 and camera body 3 in anoperating situation in which camera shake is likely to occur, thethreshold at which the mode is shifted to sensitivity increasing mode islowered to minimize the influence of camera shake so that sensitivity isincreased earlier even by risking image quality.

A case has been explained in the present embodiment where the focallength f is 300 mm as shown in FIG. 15 as an example of the focal lengthf as a threshold switching condition, but the present invention is notlimited to this value. Furthermore, threshold A may be changed accordingto not only the focal length f of replacement lens 2, but also otherinformation such as a full-aperture F number. Especially when thefull-aperture F number is small (e.g. F2), the influence of camera shakeis insignificant, and so threshold A may be increased, while when thefull-aperture F number is large (e.g. F8), the influence of camera shakeis significant, and so threshold A may be lowered.

Returning to the flowchart in FIG. 13, if, as a result of a comparisonin step S17, the moving speed Vh is equal to or above threshold A, bodymicrocomputer 12 judges that the subject is moving at a speed subjectshake does not occur, and moves the step to step S22. By contrast, whenthe moving speed Vh is below threshold A, body microcomputer 12 judgesthat subject shake does not occur, and moves the step to step S18. In asituation in which no subject shake occurs, ISO sensitivity, which isphotographing sensitivity, is set equivalent to 64 and the shutter speedis set to 1/30 seconds and so on.

In step S18, body microcomputer 12 continues camera shake correctionmode as the photographing mode and makes one of camera body camera shakecorrecting apparatus 75 in camera body 3 and replacement lens camerashake correcting apparatus 82 in replacement lens 2 operate.

In step S19, upon recognizing that the photographer has fully pressedshutter operation section 53, body microcomputer 12 moves the step tostep 20. In this step S20, photographing process is performed. That is,in step S20, an image of the subject is formed on imaging sensor 11 andan image signal is outputted. The image signal outputted is displayed ondisplay section 16. In this case, ISO sensitivity, which isphotographing sensitivity, is displayed on display section 16, inaddition to the photographed image.

In step S21, the image signal obtained in step S20 is recorded by imagereading/recording section 18 and the photographing process is finished.Furthermore, when recording the image signal, the position of AF area Fawith respect to the entire photographed image is also recorded.Photographing is not limited to photographing of one photograph, butcontinuous shooting may also be performed.

Thus, when the moving speed Vh of the face of the subject is belowthreshold A, photographing sensitivity is not changed and the camerashake correcting function operates. This makes it possible to reducecamera shake caused by a shaking hand and so on and photograph images ofhigh image quality.

On the other hand, if, as a result of the comparison in step S17, themoving speed Vh is equal to or above threshold A, body microcomputer 12moves the step to step S22. In this step S22, body microcomputer 12switches the photographing mode to sensitivity increasing mode. That is,digital signal gain setting section 111 sets a gain such that thephotographing sensitivity is high. Here, body microcomputer 12 setsphotographing sensitivity according to the moving speed of the face ofthe subject. To be more specific, body microcomputer 12 calculates theshutter speed free of subject shake from the moving speed Vh of the faceof the subject and sets photographing sensitivity with whichphotographing at the calculated shutter speed is possible. For example,upon photographing a subject that is moving slowly at a walking speed inan outdoor environment, photographing sensitivity equivalent to ISOsensitivity 100 is set, and, upon photographing a subject that is movingat a running speed, photographing sensitivity equivalent to ISOsensitivity 400 is set, and in this way photographing sensitivity is setaccording to the moving speed of the face of the subject. As forphotographing sensitivity, an upper limit may be set to suppress thequality degradation of photographed images. That is, in the case ofsensitivity increasing mode, an upper limit of ISO sensitivity may beautomatically set equivalent to ISO sensitivity 1600 so that the upperlimit may be lowered compared to the case the upper limit can be setequivalent to up to ISO sensitivity 3200 when a regular photograph istaken. Furthermore, when an upper limit is set manually, the upper limitmay be set such that it can only be set to a value lower than when aregular photograph is taken.

In step S23, upon recognizing that the photographer has fully pressedshutter operation section 53, body microcomputer 12 moves the step tostep S24. In this step S24, photographing process is performed. That is,in step S24, an optical image of the subject is formed on imaging sensor11 and imaging sensor 11 outputs an image signal. Digital signalamplification section 110 amplifies the image signal outputted fromdigital signal processing section 68 by the gain set in step S12.

Thus, in sensitivity increasing mode, photographs are taken in highsensitivity, that is, in higher ISO sensitivity than in normal mode orin camera shake correction mode. Furthermore, the exposure time is setshort in this case so that the exposure value stays substantially thesame.

In step S25, the image signal amplified in step S24 is recorded in imagereading/recording section 18 and the photographing process is finished.Furthermore, when the image signal is recorded, the position of the AFarea Fa with respect to the entire photographed image is also recordedat the same time. Photographing is not limited to taking one shot, andcontinuous shooting may also be performed. Furthermore, in photographingsensitivity increasing mode, the camera shake correcting apparatus mayor may not be operated.

Here, when continuous shooting is performed in step S21 and step S25,the following processing is performed. When performing continuousshooting, performing continuous shooting processing itself does no, butthe point in this continues shooting lies in taking a plurality ofphotographs (e.g. four photographs here) on a continuous basis based ondifferent exposure conditions. That is, four photographs are takencontinuously in one second, by operating shutter operation section 53one time here. Furthermore, the photographing sensitivity is increasedper shot. This is because the moving speed Vh of the subject is assumedto increase while photographs are taken. For example, digital signalgain setting section 111 sets the gain so that the photographingsensitivity is increased from ISO sensitivity 200 equivalents.

When, for example, four photographs are taken on a continuous basis, anoptical image of the subject is first formed on imaging sensor 11 whenthe first photograph is taken, and imaging sensor 11 outputs an imagesignal. Digital signal amplification section 110 then amplifies theimage signal outputted from digital signal processing section 68 by again set equivalent to ISO sensitivity 200. In this case, the shutterspeed is set to 1/60 seconds. Next, when the second photograph is taken,an optical image of the subject is formed on imaging sensor 11 andimaging sensor 11 outputs an image signal. Digital signal amplificationsection 110 amplifies the image signal outputted from digital signalprocessing section 68 by a gain set equivalent to ISO sensitivity 400.In this case, the shutter speed is set to 1/125 seconds. Next, when thethird photograph is taken, an optical image of the subject is formed onimaging sensor 11 and imaging sensor 11 outputs an image signal. Digitalsignal amplification section 110 amplifies the image signal outputtedfrom digital signal processing section 68 by a gain set equivalent toISO sensitivity 800. In this case, the shutter speed is set to 1/250seconds. Finally, when the fourth photograph is taken, an optical imageof the subject is formed on imaging sensor 11 and imaging sensor 11outputs an image signal. Digital signal amplification section 110amplifies the image signal outputted from digital signal processingsection 68 by a gain set equivalent to ISO sensitivity 1600. In thiscase, the shutter speed is set to 1/500 seconds.

Thus, in sensitivity increasing mode for continuous shooting, takingphotographs in high sensitivity, that is, taking photographs in higherISO sensitivity than in normal mode or camera shake correction mode isperformed. Furthermore, the exposure time is set short such that theexposure value stays substantially the same.

The four photographed images taken by continuous shooting are obtainedwith ISO sensitivity and shutter speed changed so as to keep theexposure value constant, and the four photographed images taken bycontinuous shooting may be displayed in thumbnails on display section 16after photographs have been taken. In this case, thumbnail displaynumber 1 to 4 and each ISO sensitivity are displayed on display section16.

Furthermore, as for the four photographed images taken by continuousshooting, the four images may be automatically recorded or thephotographer may arbitrary select and save images.

Thus, when the moving speed Vh of the face of the subject is abovethreshold A, the photographing sensitivity is set to high sensitivity.This makes it possible to shorten the exposure time and realizephotographing at a faster shutter speed, thereby preventing subjectshake. In photographing sensitivity increasing mode, the camera shakecorrecting apparatus may or may not be made to operate.

As described above, according to the present embodiment, when digitalsingle-lens reflex camera 1 changes the photographing mode tosensitivity increasing & camera shake correction automatic selectionmode, quick return mirror 4 is automatically brought up and the focusdetection scheme is changed from a phase difference detection scheme toa contrast detection scheme. Furthermore, a live view is displayed ondisplay section 16 to allow photographing using display section 16.

Furthermore, a motion vector is detected through contrast detection andif the subject speed is equal to or above threshold A, photographingsensitivity is increased. By contrast, if the subject speed is belowthreshold A, camera shake correction is made to operate to suppress theinfluence of the shake of the photographer's hand.

Furthermore, camera body 3 reads information such as the focal length ofreplacement lens 2 and full-aperture F number and sets an optimumthreshold in individual replacement lens 2 based on this information.

Furthermore, if camera shake correcting apparatus 82 is mounted onreplacement lens 2, the photographing mode is automatically shifted tosensitivity increasing & camera shake correction mode. On the otherhand, if camera shake correcting apparatus 82 is not mounted onreplacement lens 2, the photographing mode is automatically shifted tosensitivity increasing mode.

As described so far, digital single-lens reflex camera 1 can alsophotograph images of high quality free of camera shake or subject shake.Furthermore, camera body 3 reads information about replacement lens 2,thereby setting a photographing condition and a photographing mode thatis suitable for replacement lens 2.

The present embodiment is digital single-lens reflex camera 1 comprisedof camera body 3 and replacement lens 2 detachably mounted on camerabody 3. A compact digital camera generally includes an imaging sensor, afocusing means that performs focus detection based on a contrast schemeusing the imaging sensor, a motion detecting means that detects a thesubject speed from an image on the imaging sensor, and a camera shakecorrecting means that performs camera shake correction according to thesubject speed detected in the motion detecting means. Furthermore, whenthe lens is used to take photographs, the single-lens reflex camerachanges the position of a return mirror fast and retracts the returnmirror from the photographing optical path, thereby switching the finderoptical path to a photographing optical path and enabling the returnmirror to return to its regular position when photographs have beentaken. However, conventional digital single-lens reflex cameras having amovable return mirror do not have a system that performs camera shakecorrection realized in compact digital cameras. The present embodimentprovides a digital single-lens reflex camera including monitorphotographing mode with a camera shake correcting function.

Furthermore, there are already many conventional replacement lenseshaving a camera shake correcting apparatus that corrects the shake ofoptical images. The digital single-lens reflex camera according to thepresent embodiment is extremely useful from the standpoint ofeffectively making the most of resources of these replacement lenseshaving a camera shake correcting apparatus.

Furthermore, the present embodiment calculates the subject speed basedon the motion of the detected subject, decides whether or not thesubject speed is equal to or above threshold A, operates, if the subjectspeed is below threshold A, one of camera body camera shake correctingapparatus 75 in camera body 3 and replacement lens camera shakecorrecting apparatus 82 in replacement lens 2 and increases, if thesubject speed is equal to or above threshold A, the gain of digitalsignal gain setting section 111, increases ISO sensitivity, increasesthe shutter speed, shortens the exposure time and photographs aplurality of images continuously based on different exposure conditionsby one shutter operation, thereby reducing image quality degradationcaused by camera shake or subject shake and allowing photographs to betaken in high quality at ease.

To be more specific, if the motion of the subject is fast, thephotographing sensitivity is changed to high sensitivity, the exposuretime is shortened and a photograph is taken at a fast shutter speed.This can prevent image quality degradation caused by subject shake. Onthe other hand, if the motion of the subject is slow, one of camera bodycamera shake correcting apparatus 75 in camera body 3 and replacementlens camera shake correcting apparatus 82 in replacement lens 2 is madeto operate, thereby making it possible to prevent camera shake caused bya shaking hand and reduce image quality degradation. Therefore, thephotographer can simply take a photograph regardless of the motion ofthe subject.

Furthermore, if the motion of the subject is fast, the photographingsensitivity is automatically changed to high sensitivity, and thereforethe photographer need not observe the motion of the subject and decidewhether or not subject shake occurs, and a high degree of convenience isthereby provided.

Furthermore, if the detected subject speed is equal to or abovethreshold A, the present embodiment changes photographing sensitivity tohigh sensitivity. This prevents the photographer from wrongly settinghigh photographing sensitivity although the subject is moving at a speedto cause subject shake.

Especially according to the present embodiment, at the time of shutterfull-press operation after change to sensitivity increasing mode,continuous shooting is performed based on a plurality of exposureconditions by one shutter operation, allowing the photographer to takephotographs based on a plurality of exposure conditions at a time. Inthis case, by increasing the photographing sensitivity and shutter speedper shot, it is possible to also support a case where the moving speedVh of the subject increases while photographs are taken. Even thesituation in which the moving speed of the subject changes substantiallythe moment the photographer fully presses shutter operation section 53(for example, when photographing a child) can be sufficiently supportedby taking photographs by increasing the shutter speed during continuousshooting. By photographing a subject continuously based on a pluralityof exposure conditions and recording photographed images, even if themoving speed of the subject changes substantially while photographs aretaken, there is a high possibility that images of high image quality maybe included in one of a plurality of images photographed on a continuousbasis under the plurality of exposure conditions, and, consequently,images free of subject shake are recorded. Therefore, the photographercan select a thumbnail display number from buffer memory 69 in whichfour images photographed on a continuous basis based on differentexposure conditions are recorded, and save the best image free ofsubject shake.

Furthermore, instead of detecting the overall the motion of the subject,the motion of the face of the subject is focused among various motionsof the subject, and if the motion of the face of the subject is slow,one of camera shake correcting apparatus 75 in camera body 3 and camerashake correcting apparatus 82 in replacement lens 2 is made to operate,and if the motion of the face of the subject is fast, photographingsensitivity is changed to high sensitivity, and it is thereby possibleto switch from camera shake correction control to photographingsensitivity control with high sensitivity according to the motion of theface of the subject which is assumed to be the one expected by thephotographer to be photographed with the highest quality. Therefore,even if the moving speed of part or whole of the detected subject isequal to or above threshold A, if the motion of the face of the subjectis below threshold A, camera shake correction mode is continued and doesnot change to sensitivity increasing mode. That is, camera shakecorrection mode is continued as long as possible until the motion of theface of the subject exceeds threshold A, and it is not until the motionof the face of the subject exceeds threshold A that the mode is shiftedto sensitivity increasing mode. For example, in a situation in which thesubject is a person and the person is waving his/her hand and his/herface does not show much motion, the mode does not shift to sensitivityincreasing mode, thus preventing photographing sensitivity fromincreasing more than necessary. If the subject speed is slow, this canprevent deterioration of image quality caused when ISO sensitivity isincreased. Since it is assumed that the photographer may consider itbest to photograph the face of the subject, ISO sensitivity is notincreased if the face does not move. Although subject motion detectionhas been performed preferentially for the face of the subject, a systemis also possible that allows the photographer to arbitrarily adopt asetup for judging the motion of the subject based on the overall motionof the subject. Furthermore, as for detection of the motion of thesubject, the motion of the eyes of the subject in particular is detectedand when, for example, a person blinks and closes his/her eyes, thesubject may be judged to have moved and ISO sensitivity may beincreased.

The imaging control according to the present embodiment might proveespecially useful for telephotography in, for example, athletic meets,and the present embodiment is especially effective when used in such asituation. By detecting the motion of the face of the subject anddetermining photographing sensitivity, even if, for example, thesubject's hand or foot moves, it is not necessary to increasephotographing sensitivity more than necessary, thereby preventingdegradation of image quality caused by increased photographingsensitivity.

Here, the relationship between change in the speed of the subject andphotographing sensitivity, during the period from a shutter half-pressoperation, via a shutter full-press operation, to photographing will beexplained.

FIG. 17 illustrates a relationship between the moving speed Vh of thesubject and photographing sensitivity S upon taking a photograph. InFIG. 17, T1 denotes shutter half-press operation timing, T2 denotesshutter full-press operation timing and T3 denotes photographing timing.Furthermore, S1 to S4 denote photographing sensitivity upon taking aphotograph and A denotes a threshold. Whether the subject speed Vh isequal to or above threshold A is judged, and if the subject speed isbelow threshold A, one of camera shake correcting apparatus 75 in camerabody 3, and camera shake correcting apparatus 82 in replacement lens 2is made to operate and when the subject speed Vh is equal to or abovethreshold A, the ISO sensitivity is increased or the shutter speed isincreased (either one or both of the ISO sensitivity and shutter speedmay be increased). Although the present embodiment has two values,threshold A1 for normal photographing mode and threshold A2 for highsensitivity preferential photographing mode (where A1>A2), suppose A1and A2 are represented by threshold A here in the explanations below.

The present embodiment starts motion vector detection for the subject insynchronization with the shutter half-press operation (step S15 in FIG.13). Motion vector detection is performed until immediately before ashutter full-press operation (step S18 and step S22 in FIG. 13) everycertain period and the subject speed at the time a shutter full-pressoperation is made the final subject speed Vh. In this case, in FIG. 17,assuming (1) is a case where there is no the motion of the subject, (2)is a case where the subject is moving at constant speed, (3) is a casewhere the subject is accelerating at a certain rate and (4) is a casewhere the subject is decelerating at a certain rate, the relationshipbetween change in the speed of the subject and photographing sensitivityupon taking the first photograph, is as follows.

(1) When subject speed Vh during shutter half-press operation is belowthreshold A and constant

In this case, since the subject speed Vh is below threshold A,photographing sensitivity is not increased and the sensitivity is set tophotographing sensitivity S1 in normal photographing mode.

(2) When subject speed Vh during shutter half-press operation is abovethreshold A and constant

In this case, photographing sensitivity is increased according to thesubject speed Vh during shutter full-press operation. Here, thesensitivity is set to photographing sensitivity S2.

(3) When subject speed Vh exceeds threshold A during shutter half-pressoperation and increases gradually

In this case, since the subject speed Vh increases gradually,acceleration is calculated, the amount of speed increased is predictedfor the time lag from the time of shutter full-press operation to actualphotographing and sensitivity is set to photographing sensitivity S3(S2<S3). Furthermore, in this case, it is preferable to increase thephotographing sensitivity and shutter speed per shot in the consecutiveshooting of the second and subsequent photographs.

(4) When subject speed Vh during shutter half-press operation exceedsthreshold A and slows down gradually Opposite to case (3) above, whenthe subject speed Vh slows down gradually, the amount of speed sloweddown is predicted and the sensitivity is set to photographingsensitivity S4 (S4<S2). Furthermore, in this case, it is preferable todecrease photographing sensitivity and shutter speed per shot in theconsecutive shooting of the second and subsequent photographs.

The explanations so far are illustrations of a preferable embodiment ofthe present invention and the scope of the present invention is notlimited to this.

The feature of the present invention is applicable to any apparatus aslong as it is an electronic apparatus having an imaging apparatus. Forexample, the present invention is applicable not only to a digitalcamera and video camera, but also to a mobile phone set with a camera,portable information terminal such as a PDA (Personal Digital Assistant)and information processing apparatus such as a personal computer with animaging apparatus.

Furthermore, when continuous shooting is performed, a plurality ofcontinuing photographs may be taken based on different exposureconditions and, for example, before four continuing photographs aretaken with high sensitivity, one photograph is taken with ISOsensitivity 100 equivalents which is photographing sensitivity in normalmode and a total of five photographs may be taken through normalphotographing and high sensitivity photographing by one shutteroperation.

Furthermore, in camera shake correction mode, continuous shooting may beperformed by one shutter operation by a plurality of exposureconditions. This allows the photographer to take photographs based on aplurality of exposure conditions at a time. In this case, thephotographing sensitivity of the first photograph is the same ISOsensitivity as in regular photographing. For the second and subsequentphotographs, even the case where the moving speed Vh of the subjectincreases while photographs are taken can also be supported byincreasing the photographing sensitivity and shutter speed per shot.Even a situation in which the moving speed of the subject changessubstantially the moment the photographer fully presses shutteroperation section 53 (for example, when taking a photograph of a child)can be sufficiently supported by taking photographs by increased shutterspeed in the case of continuous shooting. Furthermore, as describedabove, photographing sensitivity and shutter speed may be changedaccording to a variation of the subject speed Vh in the middle ofshutter half-press operation.

FIG. 18 shows a display example of a photographed image with asensitivity increase and a photographed image without a sensitivityincrease displayed on display section 16 after the setup ofphotographing sensitivity increasing mode of the digital single-lensreflex camera according to the present embodiment. As shown in FIG. 18,continuous shooting may be performed by one shutter operation and imageswith increased sensitivity and images without a sensitivity increasewith different photographing sensitivities may be photographed so thatthe photographed images of two modes and image qualities may be comparedimmediately after photographs are taken or at the time of playback.Furthermore, images may be displayed enlarged centered on the AF area Faautomatically or manually using operation cross key 55 and so on so thata total of four photographed images may be displayed together on displaysection 16.

Furthermore, when a photograph is taken using a self-timer and so on,the motion of the optical image of the subject may be detected from afew seconds after shutter operation section 53 is fully pressed untilphotographs start being taken. More preferably, an LED and so on may beprovided in the front of digital camera 1 and made to blink duringmotion detection so that the blinking may be recognized from the subjectside.

The configuration of the imaging optical system and camera shakecorrecting section according to the present embodiment is not limited tothe above-described configuration. Replacement lens camera shakecorrecting apparatus 82 may also have, for example, a configuration inwhich the angle of the prism provided in the front of replacement lens 2on the subject side may be changed and the configuration thereof is notlimited to such a configuration if the configuration at least allowscamera shake correction. Furthermore, camera body camera shakecorrecting apparatus 75 may also be based on an electronic type camerashake correction scheme whereby an image extracting position in imagingsensor 11 may be changed and corrected or a plurality of photographs ofthe same subject may be taken at a short shutter speed and then combinedas one image and so on and it is obvious that the scheme thereof is notlimited.

Furthermore, a case has been described with the present embodiment wherethe time of exposure to the imaging sensor is controlled by operatingthe shutter, but the present invention is not limited to this and theexposure time of the imaging sensor may be controlled through anelectronic shutter and so on.

Furthermore, a case has been described with the present embodiment as anexample where a plurality of images can be photographed continuously byoperating shutter operation section 53 one time, but such a system maybe adopted that photographs can be taken only in the period in whichshutter operation section 53 is operated (e.g. pressed).

Furthermore, the present embodiment uses the name “digital single-lensreflex camera,” but this is for convenience of explanation and it goeswithout saying that the name may also be a “photographing apparatus,”“digital camera” or “imaging method.”

Furthermore, the components making up the above-described digitalsingle-lens reflex camera, for example, the type of the imaging opticalsystem, the drive section thereof and mounting method and so on orfurther the type of the motion detecting section are not limited tothose of the embodiments above.

Furthermore, the digital single-lens reflex camera explained so far mayalso be implemented by a program for executing the photographing controlmethod for this digital single-lens reflex camera. This program isstored in a computer-readable recording medium.

The disclosure of Japanese Patent Application No. 2007-180318, filed onJul. 9, 2007, including the specification, drawings and abstract isincorporated herein by reference in its entirety.

INDUSTRIAL APPLICABILITY

The digital single-lens reflex camera according to the present inventionis suitable for use in a digital still camera, digital video camera,mobile phone provided with a camera section and PDA and so on for whichimages of high image quality are required.

1. A digital single lens reflex camera with an imaging sensor and areturn mirror, the camera comprising: a focusing section that performsfocus detection based on a contrast scheme using the imaging sensor; amotion detecting section that detects a speed of the subject based on animage on the imaging sensor; a control section that performs camerashake correction according to the speed of the subject detected in themotion detecting section; a camera shake correcting section that ismounted in at least one of a camera body and a replacement lens and thatcorrects shake of an optical image caused by motion of the camera body;and a detecting section that detects the presence and absence of thecamera shake correcting section on the replacement lens side, whereinthe focusing section, the motion detecting section and the controlsection enter operation mode while the return mirror is retracted fromthe optical axis, wherein the control section increases an amplificationfactor of the image or shortens an exposure time when the subject speeddetected in the motion detecting section is equal to or higher than athreshold, or controls the camera shake correcting section to executecamera shake correction when the subject speed detected in the motiondetecting section is lower than the threshold, and wherein, when thereplacement lens has the camera shake correcting section, the controlsection controls the camera shake correcting section via an interfacesection.
 2. The digital single lens reflex camera according to claim 1,wherein, when the subject speed detected in the motion detecting sectionis equal to or higher than the threshold, the control section providesvarying exposure times or amplification factors and causes a photographto be taken a plurality of times.
 3. The digital single lens reflexcamera according to claim 2, wherein the control section causes aphotograph to be taken a plurality of times by controlling the exposuretime to be shorter per shot or by controlling the amplification factorto be higher per shot.
 4. The digital single lens reflex cameraaccording to claim 1, wherein the control section predicts a subjectspeed when a photograph is taken based on an amount of variation of thesubject speed within a predetermined time and controls an exposure timeor amplification factor according to the predicted subject speed.
 5. Thedigital single lens reflex camera according to claim 1, wherein thecontrol section changes the threshold based on focal length informationabout the replacement lens used.
 6. The digital single lens reflexcamera according to claim 1, wherein the control section changes thethreshold depending on whether the camera shake correcting section ismounted on the camera body side or the replacement lens side.
 7. Adigital single lens reflex camera with an imaging sensor and a returnmirror, the camera comprising: a focusing section that performs focusdetection based on a contrast scheme using the imaging sensor; a motiondetecting section that detects a speed of the subject based on an imageon the imaging sensor; a control section that performs camera shakecorrection according to the speed of the subject detected in the motiondetecting section; and a camera shake correcting section that is mountedin at least one of a camera body and a replacement lens and thatcorrects shake of an optical image caused by motion of the camera body;wherein the focusing section, the motion detecting section and thecontrol section enter operation mode while the return mirror isretracted from the optical axis, wherein the control section increasesan amplification factor of the image or shortens an exposure time whenthe subject speed detected in the motion detecting section is equal toor higher than a threshold, or controls the camera shake correctingsection to execute camera shake correction when the subject speeddetected in the motion detecting section is lower than the threshold;and wherein the control section switches between shake correctionperformed electrically through control over the amplification factor orexposure time on the camera body side, and shake correction performedoptically by the camera shake correcting section on the replacement lensside according to the subject speed detected in the motion detectingsection.
 8. The digital single lens reflex camera according to claim 7,wherein the control section changes the threshold based on focal lengthinformation about the replacement lens used.
 9. The digital single lensreflex camera according to claim 7, wherein the control section changesthe threshold depending on whether the camera shake correcting sectionis mounted on the camera body side or the replacement lens side.
 10. Thedigital single lens reflex camera according to claim 7, wherein, whenthe subject speed detected in the motion detecting section is equal toor higher than the threshold, the control section provides varyingexposure times or amplification factors and causes a photograph to betaken a plurality of times.
 11. The digital single lens reflex cameraaccording to claim 10, wherein the control section causes a photographto be taken a plurality of times by controlling the exposure time to beshorter per shot or by controlling the amplification factor to be higherper shot.
 12. The digital single lens reflex camera according to claim7, wherein the control section predicts a subject speed when aphotograph is taken based on an amount of variation of the subject speedwithin a predetermined time and controls an exposure time oramplification factor according to the predicted subject speed.